Fluid ejection device, driving method of fluid ejection device, and operating instrument

ABSTRACT

A fluid ejection device includes: a fluid chamber whose capacity is variable; an inlet flow path and an outlet flow path communicating with the fluid chamber; a capacity changing unit which changes the capacity of the fluid chamber; a fluid supplying unit which supplies fluid to the inlet flow path; a fluid ejection opening disposed at an end of the outlet flow path opposite to an end communicating with the fluid chamber; a vibrating unit which vibrates a component in the vicinity of the fluid ejection opening; a vibration detecting unit which detects the level of vibration of the component in the vicinity of the fluid ejection opening; and an operation control unit which controls operation of the capacity changing unit based on the level of the vibration detected by the vibration detecting unit.

This is a Continuation Application of application Ser. No. 12/568,156filed Sep. 28, 2009 which claims priority to Japanese Patent ApplicationNo. 2008-256092 filed on Oct. 1, 2008, and is hereby incorporated byreference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a fluid ejection device which ejectsfluid at high speed, and more particularly to a fluid ejection device, adriving method of a fluid ejection device, and an operating instrumentcapable of controlling fluid ejection according to contact conditionbetween an ejection target object and an ejection end.

2. Related Art

A fluid ejection device which opens or removes tissue of a living bodyby cutting has been proposed by the present inventors (seeJP-A-2008-82202).

This fluid ejection device includes: a pulse generating unit which has afluid chamber whose capacity is variable, inlet flow path and outletflow path communicating with the fluid chamber, a capacity changing unitfor changing the capacity of the fluid chamber according to supply ofdriving signals; a connection flow path which has one end communicatingwith the outlet flow path and the other end having a fluid ejectionopening (nozzle) whose diameter is smaller than that of the outlet flowpath; a connection flow pipe containing the connection flow path andhaving rigidity sufficient for transmitting pulse of fluid flowing fromthe fluid chamber to the fluid ejection opening; and a pressuregenerating unit which generates pressure for supplying fluid to theinlet flow path. The fluid ejection device supplies fluid to the inletflow path with constant pressure produced by the pressure generatingunit, and generates pulse by changing the capacity of the fluid chamberusing the capacity changing unit to deliver fluid.

When the capacity of the fluid chamber of the fluid ejection device isnot changed, fluid flows under the balanced condition between supplypressure produced by the pressure generating unit and fluid pathresistance. In this condition, delivery of fluid from the nozzle iscontinuous at low speed, producing substantially no tissue cuttingcapability.

When the capacity of the fluid chamber is rapidly decreased, thepressure of the fluid chamber increases. In this condition, increase inthe flow amount of fluid delivered from the outlet flow path is largerthan decrease in the flow amount of fluid flowing into the fluid chamberfrom the inlet flow path. Thus, pulsed flow is generated in theconnection flow path. This pressure change at the time of delivery istransmitted through the connection flow path pipe such that fluid can beejected from the fluid ejection opening formed at the end of the nozzleat high speed.

By repeating this operation, fluid can be delivered by highspeed pulsejet. In this structure, starting and stopping at the speed of severalmsec. or lower can be achieved by contracting and expanding the fluidchamber using a piezoelectric element.

This technology is applicable to a fluid ejection device disclosed inanother reference (see JP-A-2005-152127) proposed by the presentinventors as ejection device requiring no pressure generating unit.

When the fluid ejection device in the related art discussed above isused as a water scalpel in an operation, the operation is performed withthe nozzle almost closely attached to the affected part. Thus, when thenozzle ejecting fluid is separated from the affected part, liquid dropsproduced by the fluid ejection are scattered. In this case, there is apossibility that removed pieces of tissue containing cancer or the likeare scattered around.

SUMMARY

It is an advantage of some aspects of the invention to provide a fluidejection device, a driving method of a fluid ejection device, and anoperating instrument capable of controlling fluid ejection operationaccording to contact condition between an ejection target object and anejection end.

First Aspect

A first aspect of the invention is directed to a fluid ejection deviceincluding: a fluid chamber whose capacity is variable; an inlet flowpath and an outlet flow path communicating with the fluid chamber; acapacity changing unit which changes the capacity of the fluid chamber;a fluid supplying unit which supplies fluid to the inlet flow path; afluid ejection opening disposed at an end of the outlet flow pathopposite to an end communicating with the fluid chamber; a vibratingunit which vibrates a component in the vicinity of the fluid ejectionopening; a vibration detecting unit which detects the level of vibrationof the component in the vicinity of the fluid ejection opening; and anoperation control unit which controls operation of the capacity changingunit based on the level of the vibration detected by the vibrationdetecting unit.

According to this structure, the pressure inside the fluid chamberchanges to produce pulsed flow when the capacity of the fluid chamber isvaried by the capacity changing unit. Then, the pulsed flow passesthrough the outlet flow path to be ejected through the fluid ejectionopening.

When the vibrating force is applied to the component in the vicinity ofthe fluid ejection opening by the vibrating unit, the component in thevicinity of the fluid ejection opening and the fluid ejection openingvibrate.

After the level of the vibration of the component in the vicinity of thefluid ejection opening is detected by the vibration detecting unit, theoperation of the capacity changing unit is controlled by the operationcontrol unit according to the detected level of the vibration.

When the vibrating fluid ejection opening contacts a fluid ejectiontarget object or an object in the vicinity of the target object (such asliquid reservoir of ejected fluid), the levels of the vibrations of thefluid ejection opening and the component in the vicinity of the fluidejection opening vary (decrease). Then, this change is detected by thevibration detecting unit.

Based on this detection, the operation control unit controls theoperation of the capacity changing unit to prohibit capacity changingoperation or decrease fluid ejecting force when the level of thevibration detected by the vibration detecting unit corresponds to thelevel obtained at the time when the fluid ejection opening contactsnothing, for example.

When the level of the vibration detected by the vibration detecting unitcorresponds to the level obtained at the time when the fluid ejectionopening contacts the ejection target object or the object in thevicinity of the ejection target object (smaller vibration than vibrationat the time of non contact), the operation control unit controls theoperation of the capacity changing unit to change the capacity, forexample.

By this method, ejection operation can be prohibited or ejecting forcecan be decreased when the fluid ejection opening does not contact theejection target object or the object in the vicinity of the ejectiontarget object. Thus, ejection of fluid in an unexpected direction andscattering of substances cut thereby can be prevented when the fluidejection opening is separated from the ejection target object or theobject in the vicinity of the ejection target object by operation erroror the like of a user (hereinafter referred to as operator as well).

It is preferable that the component in the vicinity of the fluidejection opening vibrates when vibrating force is applied to thecomponent, and that the level of the vibration of the component varies(decreases, for example) when the end portion containing the fluidejection opening contacts an object (such as solid and liquid).

Second Aspect

A second aspect of the invention is directed to the fluid ejectiondevice of the first aspect, wherein the component in the vicinity of thefluid ejection opening forms the fluid ejection opening.

According to this structure, the component forming the fluid ejectionopening vibrates when the vibrating unit applies vibrating force to thecomponent forming the fluid ejection opening.

When the vibration detecting unit detects the level of the vibration ofthe fluid ejection opening, the operation control unit controls theoperation of the capacity changing unit based on the detected level ofthe vibration.

Third Aspect

A third aspect of the invention is directed to the fluid ejection deviceof the first aspect, wherein the fluid ejection device further includes:a suction pipe having a suction opening positioned in the vicinity ofthe fluid ejection opening and a passage through which an object suckedvia the suction opening passes; and a sucking force giving unit whichgives sucking force for sucking an object in the vicinity of the suctionopening. The component in the vicinity of the fluid ejection openingforms the suction opening.

According to this structure, the object in the vicinity of the suctionopening (such as fluid ejected from the fluid ejection opening andtissue pieces or other object cut or removed by fluid ejection) issucked when sucking force is given by the sucking force giving unit.Then, the sucked object passes through the passage formed inside thesuction pipe to be conveyed to a container for storing sucked object orthe like.

When the vibrating unit applies vibrating force to the component formingthe suction opening, the suction opening vibrates.

After the vibration detecting unit detects the level of the vibration ofthe suction opening, the operation control unit controls the operationof the capacity changing unit according to the detected level of thevibration.

When the vibrating suction opening contacts a fluid ejection targetobject or an object in the vicinity of the ejection target object (suchas liquid reservoir of ejected fluid), the level of the vibration of thesuction opening varies (decreases, for example). This change is detectedby the vibration detecting unit.

Based on this detection, the operation control unit controls theoperation of the capacity changing unit to prohibit capacity changingoperation or decrease fluid ejecting force when the level of thevibration detected by the vibration detecting unit corresponds to thelevel obtained at the time when the suction opening contacts nothing,for example.

When the level of the vibration detected by the vibration detecting unitcorresponds to the level obtained at the time when the suction openingcontacts the ejection target object or the object in the vicinity of theejection target object (smaller vibration than vibration at the time ofnon contact), the operation control unit controls the operation of thecapacity changing unit to change the capacity, for example.

By this method, ejection operation can be prohibited or ejecting forcecan be decreased when the suction opening does not contact the ejectiontarget object or the object in the vicinity of the ejection targetobject. Thus, ejection of fluid in an unexpected direction andscattering of substances cut thereby can be prevented when the suctionopening and the fluid ejection opening are separated from the ejectiontarget object or the object in the vicinity of the ejection targetobject by operation error or the like of the operator.

Moreover, when the fluid ejection device having this structure is usedas water scalpel in an operation, for example, cut tissue pieces of aliving body or delivered fluid can be sucked by the fluid ejectiondevice. Thus, operation can be performed with preferable view secured.

Fourth Aspect

A fourth aspect of the invention is directed to the fluid ejectiondevice of the first or second aspect, wherein: the vibrating unit has avibrating force generating section which generates vibrating force forvibrating the fluid ejection opening; the vibration detecting unit has avibration receiving section which receives vibration; and the vibratingforce generating section and the vibration receiving section areprovided on the outlet flow path.

According to this structure, vibrating force applied to the outlet flowpath using the vibrating force generating section vibrates the fluidejection opening or the component in the vicinity of the fluid ejectionopening. This vibration is received by the vibration receiving section.

Fifth Aspect

A fifth aspect of the invention is directed to the fluid ejection deviceof the fourth aspect, wherein: a flat surface is provided at least on apart of the outer circumferential surface of the outlet flow path; andthe vibrating force generating section and the vibration receivingsection are provided on the flat surface.

According to this structure, the vibrating force generating section andthe vibration receiving section formed by material difficult to bebended can be easily attached to the outlet flow path while maintainingstraight shapes.

Sixth Aspect

A sixth aspect of the invention is directed to the fluid ejection deviceof the third aspect, wherein: the vibrating unit has a vibrating forcegenerating section which generates vibrating force for vibrating thesuction opening; the vibration detecting unit has a vibration receivingsection which receives vibration; and the vibrating force generatingsection and the vibration receiving section are provided on the suctionpipe.

According to this structure, vibrating force applied to the suction pipeby the vibrating force generating section vibrates the suction opening.This vibration is received by the vibration receiving section.

Seventh Aspect

A seventh aspect of the invention is directed to the fluid ejectiondevice of the sixth aspect, wherein: a flat surface is provided at leaston a part of the outer circumferential surface of the suction pipe; andthe vibrating force generating section and the vibration receivingsection are provided on the flat surface.

According to this structure, the vibrating force generating section andthe vibration receiving section formed by material difficult to bebended can be easily attached to the suction pipe while maintainingstraight shapes.

Eighth Aspect

An eighth aspect of the invention is directed to the fluid ejectiondevice of any of fourth through seventh aspects, wherein the vibrationreceiving section has a distortion gauge.

According to this structure, the level of vibration can be easilydetected by the distortion gauge.

Ninth Aspect

A ninth aspect of the invention is directed to the fluid ejection deviceof any of the fourth through eighth aspects, wherein the vibrating forcegenerating section has a piezoelectric element.

According to this structure, vibrating force is generated by thepiezoelectric element. Thus, vibrating force can be easily controlled bycontrolling applied voltage.

Tenth Aspect

A tenth aspect of the invention is directed to the fluid ejection deviceof the eighth aspect, wherein the vibrating force generating section hasfunction of generating vibrating force and function of receivingvibration as the vibration receiving section by using the piezoelectricelement for generating vibrating force.

According to this structure, both generation of vibrating force andreception of vibration are achieved by one piezoelectric element. Thus,the vibrating unit and the vibration detecting unit can be manufacturedat relatively low cost.

Eleventh Aspect

An eleventh aspect of the invention is directed to the fluid ejectiondevice of the tenth aspect, wherein: the vibrating unit has a drivesection which drives the piezoelectric element; the vibration detectingunit has an electromotive force detecting section which detectselectromotive force generated on the piezoelectric element; and a timedivision control unit which controls the drive section and theelectromotive force detecting section such that supply of drive signalsby the drive section and detection of electromotive force by theelectromotive force detecting section are performed by time division isprovided.

According to this structure, both generation of vibrating force andreception of vibration are achieved by one piezoelectric element. Thus,the vibrating unit and the vibration detecting unit can be manufacturedat relatively low cost.

Twelfth Aspect

A twelfth aspect of the invention is directed to the fluid ejectiondevice of any of the fourth through eleventh aspects, wherein: thevibrating unit has the plural vibrating force generating sections; andthe vibrating unit controls operations of the vibrating force generatingsections such that forces generated by the plural vibrating forcegenerating sections can increase the vibrating force.

According to this structure, larger vibrating force is generated. Thus,an object to be vibrated can be greatly vibrated, and the detectionaccuracy of the level of vibration can be increased.

Thirteenth Aspect

A thirteenth aspect of the invention is directed to the fluid ejectiondevice of any of the first through twelfth aspects, wherein theoperation control unit allows operation of the capacity changing unitwhen the level of vibration detected by the vibration detecting unit islower than a predetermined level, and prohibits operation of thecapacity changing unit when the level of the vibration is equal to orhigher than the predetermined level.

According to this structure, fluid ejection is executed when the fluidejection opening or the suction opening contacts the ejection targetobject or the object in the vicinity of the fluid target object. Whenthe fluid ejection opening or the suction opening does not contact theejection target object or the object in the vicinity of the fluid targetobject, ejection is prohibited.

Fourteenth Aspect

A fourteenth aspect of the invention is directed to a driving method ofa fluid ejection device comprising: the fluid ejection device includinga fluid chamber whose capacity is variable, an inlet flow path and anoutlet flow path communicating with the fluid chamber, a capacitychanging unit which changes the capacity of the fluid chamber, a fluidsupplying unit which supplies fluid to the inlet flow path, a fluidejection opening disposed at an end of the outlet flow path opposite toan end communicating with the fluid chamber, a vibrating unit, avibration detecting unit, and an operation control unit; vibrating acomponent in the vicinity of the fluid ejection opening by the vibratingunit; detecting the level of vibration of the component in the vicinityof the fluid ejection opening by the vibration detecting unit; andcontrolling operation of the capacity changing unit based on the levelof the vibration detected in the vibration detecting step by theoperation control unit.

According to this method, operations and advantages similar to those ofthe fluid ejection device of the first aspect can be offered.

Fifteenth Aspect

A fifteenth aspect of the invention is directed to an operatinginstrument which supports medical treatment for an affected portion byusing ejection of fluid, including the fluid ejection device of any ofthe first through thirteenth aspects.

According to this structure, medical treatment for cutting and removingan affected portion such as tumor can be supported by the ejection offluid provided by the fluid ejection device described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 illustrates a general structure of a fluid ejection deviceaccording to the invention.

FIG. 2 is a cross-sectional view of a structure of a pulse generatingunit according to the invention.

FIG. 3 illustrates a disassembled fluid ejection part of the fluidejection device.

FIG. 4 is a plan view of an inlet flow path.

FIG. 5 is a block diagram showing a detailed structure of a drive unit.

FIG. 6 illustrates an attachment structure of a piezoelectric elementand a distortion gauge to a connection flow path pipe.

FIGS. 7A through 7D show other examples of the attachment structure ofthe piezoelectric element and the distortion gauge to the connectionflow path pipe.

FIG. 8 is a flowchart showing operation control process for controllinga first drive signal supplying section and a second drive signalsupplying section performed by an operation control section.

FIG. 9 is a flowchart showing drive signal supply process performed bythe first drive signal supplying section.

FIG. 10 is a flowchart showing drive signal supply process performed bythe second drive signal supplying section.

FIG. 11 shows an example of vibration waveform of a nozzle duringcontact and non-contact.

FIG. 12 illustrates a general structure of a fluid ejection deviceaccording to a second embodiment.

FIG. 13 illustrates an attachment structure of the piezoelectric elementand the distortion gauge to a suction pipe.

FIGS. 14A through 14D show other examples of the attachment structure ofthe piezoelectric element and the distortion gauge to the suction pipe.

FIG. 15A shows an example of an attachment structure of a piezoelectricelement to the connection flow path pipe. FIG. 15B shows an example ofan attachment structure of a piezoelectric element to the suction pipe.

FIG. 16 is a block diagram showing a detailed structure of a drive unit.

FIG. 17A shows vibration waveform for a period during which vibratingforce is applied by the piezoelectric element. FIG. 17B shows vibrationwaveform for a period during which vibration is received by thepiezoelectric element.

FIG. 18A shows an example of an attachment structure of piezoelectricelements to the connection flow path pipe. FIG. 18B shows an example ofan attachment structure of the piezoelectric elements to the suctionpipe.

FIG. 19 is a block diagram showing a detailed structure of a drive unit.

FIG. 20 is a flowchart showing drive signal supply process performed bya first drive signal supplying section.

DESCRIPTION OF EXEMPLARY EMBODIMENTS First Embodiment

A first embodiment according to an aspect of the invention ishereinafter described with reference to the drawings. FIGS. 1 through 9show a fluid ejection device, a driving method of the fluid ejectiondevice, and an operating instrument according to the first embodiment.

The fluid ejection device according to an aspect of the invention can beused for various applications such as drawing by ink or the like,cleaning of minute object and structure, cutting and removal of objects,and operation scalpels. In this embodiment, a water pulse scalpel (fluidejection device and operating instrument) appropriately used for openingor removing tissue of a living body by cutting will be described as anexample. Thus, fluid used in this embodiment is water, physiologicalsalt water, liquid medicine or the like.

Initially, the structure of the fluid ejection device according to thisembodiment is explained with reference to FIG. 1. FIG. 1 illustrates ageneral structure of a fluid ejection device 1 according to thisembodiment.

As illustrated in FIG. 1, the fluid ejection device 1 has a basicstructure including a fluid container 10 for storing fluid, a pump 20 asa pressure generating unit, a pulse generating unit 100 for generatingpulsed flow of fluid received from the pump 20, a drive unit 30 fordriving the pulse generating unit 100, a vibration generatingpiezoelectric element 50, and a distortion gauge 51.

The pulse generating unit 100 is connected with a pipe-shaped narrowconnection flow path pipe 200. A nozzle 211 having a smaller diameterthan the flow path diameter of the connection flow path pipe 200 isinserted into the end of the connection flow path pipe 200.

The vibration generating piezoelectric element 50 for vibrating thenozzle 211 (hereinafter abbreviated as piezoelectric element 50), andthe distortion gauge 51 for detecting the level of vibration generatedon the nozzle 211 are fixed to the outer circumferential surface of theconnection flow path pipe 200.

Passages for two supply lines VPZT(−) and VPZT(+) for supplying drivesignals to the piezoelectric element 50, gauge input line and gaugeoutput line of the distortion gauge 51, and two supply lines JPZT(−) andJPZT(+) for supplying drive signals to a fluid ejecting piezoelectricelement 401 (described later) are formed inside the pulse generatingunit 100.

These passages are joined at the exit of signal lines extended from thepulse generating unit 100, and the four supply lines and the gauge inputline and the gauge output line are collectively extended from one exitposition to the outside.

These lines are collected by a cable 45, and connected with the driveunit 30. The respective lines of the cable 45 are electrically connectedwith the corresponding components of the drive unit 30.

The flow of fluid in the fluid ejection device 1 is now brieflydescribed with reference to FIGS. 1 and 2.

FIG. 2 is a cross-sectional view showing the structure of the pulsegenerating unit 100 in this embodiment. In FIG. 2, the left-rightdirection corresponds to the up-down direction. FIG. 2 is across-sectional view taken along a line A-A′ in FIG. 4.

The fluid stored in the fluid container 10 is sucked through aconnection tube 15 using the pump 20, and supplied to the pulsegenerating unit 100 via a connection tube 25 with constant pressure. Thepulse generating unit 100 has a fluid chamber 501, and a capacitychanging unit 405 for changing the capacity of the fluid chamber 501according to drive signals sent from the drive unit 30. The pulsegenerating unit 100 generates pulse by operation of the capacitychanging unit 405, and ejects fluid at high speed through the connectionflow path pipe 200 and the nozzle 211. The details of the pulsegenerating unit 100 will be explained later.

Pressure is not required to be generated by using the pump 20 but may beproduced by supporting a liquid carry bag at a position higher than thepulse generating unit 100 using a stand or the like. In this case, thepump 20 can be eliminated, and advantages such as simplification of thestructure and easy disinfection can be provided.

The delivery pressure of the pump 20 is set at about 3 atm. (0.3 MPa) orlower. When the liquid carry bag is used, the pressure corresponds tothe height difference between the pulse generating unit 100 and theliquid level of the liquid carry bag. It is preferable that the heightdifference is so determined as to produce pressure in the range from 0.1to 0.15 atm. (0.01 to 0.15 MPa) when the liquid carry bag is used.

While performing operation using the fluid ejection device 1, theoperator holds the pulse generating unit 100. In this case, it ispreferable that the connection tube 25 extending to the pulse generatingunit 100 is flexible as much as possible. Accordingly, the connectiontube 25 is preferably a flexible and narrow tube which produces thelowest possible pressure sufficient for supplying liquid to the pulsegenerating unit 100.

Particularly when failure of the device leads to serious accidents insuch cases as brain operation, ejection of high-pressure fluid caused bycutting of the connection tube 25 or the like must be avoided. For thisreason, the pressure of the connection tube 25 is required to be keptlow.

The structure of the pulse generating unit 100 is now discussed withreference to FIGS. 2 through 4.

FIG. 3 illustrates a disassembled fluid ejection area of the fluidejection device 1. FIG. 4 is a plan view showing an inlet flow path 503on an upper case 500 as viewed from a junction surface connected with alower case 301.

As illustrated in FIGS. 2 through 4, the pulse generating unit 100includes the upper case 500 having screw holes 500 a at the fourcorners, and the lower case 301 having screw holes 301 a (not shown) atthe four corners. The upper case 500 and the lower case 301 are joinedsuch that the corresponding screw holes 500 a and 301 a are opposed toone another on the junction surfaces, and fixed to each other byinserting four fixing screws 600 (not shown) into the screw holes 500 aand 301 a.

The lower case 301 is a hollow cylindrical component having a fringeportion, and one end of the lower case 301 is closed by a bottom plate311. A piezoelectric element 401 as one of the components constitutingthe capacity changing unit 405 is provided in the space inside the lowercase 301.

The piezoelectric element 401 is a lamination type piezoelectric elementconstituting an actuator. One end of the piezoelectric element 401 isfixed to a diaphragm 400 via an upper plate 411, and the other end isfixed to an upper surface 312 of the bottom plate 311.

The diaphragm 400 is formed by a disk-shaped metal thin plate, and thecircumferential area of the diaphragm 400 is disposed within an annularconcave 303 formed on the upper surface of the lower case 301 to beclosely fixed to the bottom surface of the concave 303. A reinforcingplate 410 formed by disk-shaped metal thin plate and having a circularopening at the center is laminated on the upper surface of the diaphragm400.

According to this structure, the piezoelectric element 401 expands andcontracts in response to drive signals inputted to the piezoelectricelement 401 (operation voltage applied) from the drive unit 30. Then,the upward force at expansion and the downward force at contraction movethe upper plate 411 in the up-down direction. By movement of the upperplate 411, the diaphragm 400 deforms and changes the capacity of thefluid chamber 501.

Thus, the capacity changing unit 405 is constituted by the piezoelectricelement 401, the upper plate 411, the diaphragm 400, and the reinforcingplate 410.

The upper case 500 has a circular concave at the center of the surfaceopposed to the lower case 301. The fluid chamber 501 corresponds to arotation body formed by this circular concave and the diaphragm 400 andfilled with fluid inside. Thus, the fluid chamber 501 is a spacesurrounded by a sealing surface 505 and an inner circumferential sidewall 501 a of the concave of the upper case 500 and the diaphragm 400.An outlet flow path 511 is formed substantially at the center of thefluid chamber 501.

The outlet flow path 511 extends from the fluid chamber 501 to the endof the outlet flow path pipe 510 projecting from one end surface of theupper case 500. The connecting portion between the outlet flow path 511and the sealing surface 505 of the fluid chamber 501 is smoothly roundedto reduce fluid resistance.

While the shape of the fluid chamber 501 in this embodiment has asubstantially cylindrical shape with both ends sealed, the shape may beconical, trapezoidal, semispherical in the side view, or any arbitraryshapes. When the connecting portion between the outlet flow path 511 andthe sealing surface 505 is funnel-shaped, for example, bubbles in thefluid chamber 501 as will be described later can be easily discharged.

The connection flow path pipe 200 is connected with the outlet flow pathpipe 510. The connection flow path pipe 200 has a connection flow path201 whose diameter is larger than that of the outlet flow path 511. Thethickness of the pipe of the connection flow path pipe 200 is set insuch a range that the connection flow path pipe 200 has rigiditysufficient for absorbing no pressure pulse of fluid.

The nozzle 211 is inserted into the end of the connection flow path pipe200. The nozzle 211 has a fluid ejection opening 212. The diameter ofthe fluid ejection opening 212 is smaller than that of the connectionflow path 201.

The piezoelectric element 50 and the distortion gauge 51 are fixed tothe outer circumferential surface of the connection flow path 200 atpositions opposed to each other with the connection flow path 200disposed therebetween and positions shifted to the end from theconnection portion between the outlet flow path pipe 510 and theconnection flow path 200 on the pulse generating unit 100 side.

An inlet flow path pipe 502 to which the connection tube 25 forsupplying fluid from the pump 20 is attached is formed on the sidesurface of the upper case 500. The inlet flow path pipe 502 has an inletflow path side connection flow path 504. The connection flow path 504communicates with the inlet flow path 503. The inlet flow path 503 isformed on the periphery of the sealing surface 505 of the fluid chamber501 in the shape of groove, and communicates with the fluid chamber 501.

A packing box 304 on the lower case 301 side and a packing box 506 onthe upper case 500 side are provided on the junction surface between theupper case 500 and the lower case 301 at positions away from thediaphragm 400 in the outer circumferential direction. Also, aring-shaped packing 450 is inserted into the space formed by the packingboxes 304 and 506.

When the upper case 500 and the lower case 301 are assembled, theperiphery of the diaphragm 400 and the periphery of the reinforcingplate 410 are brought into close contact with each other by theperiphery of the sealing surface 505 of the upper case 500 and thebottom surface of the concave 303 of the lower case 301. In this case,the packing 450 is pressed by the upper case 500 and the lower case 301to prevent fluid leakage from the fluid chamber 501.

The inside space of the fluid chamber 501 has high pressure such as 30atm. (3 MPa) or higher at the time of fluid delivery. In this case,there is a possibility of slight leakage of fluid through the connectingportions of the diaphragm 400, the reinforcing plate 410, the upper case500, and the lower case 301. However, such leakage can be prevented bythe function of the packing 450.

The packing 450 disposed as illustrated in FIG. 2 is compressed bypressure of fluid leaking from the fluid chamber 501 with high pressure,and further strongly pressed by the inside walls of the packing boxes304 and 506. Thus, leakage of fluid can be more securely prevented.Accordingly, high pressure increase inside the fluid chamber 501 can bemaintained during operation.

The inlet flow path 503 formed on the upper case 500 is now explained inmore detail.

As illustrated in FIG. 4, the inlet flow path 503 has a groove formed onthe periphery of the sealing surface 505 of the upper case 500 and thereinforcing plate 410 fixed to the sealing surface 505 with pressure.

One end of the inlet flow path 503 communicates with the fluid chamber501, and the other end communicates with the connection flow path 504. Afluid reservoir 507 is provided on the connection portion between theinlet flow path 503 and the connection flow path 504. The connectionportion between the fluid reservoir 507 and the inlet flow path 503 issmoothly rounded to reduce fluid resistance.

The inlet flow path 503 communicates with the inner circumferential sidewall 501 a of the fluid chamber 501 substantially in the tangentialdirection. The fluid supplied from the pump 20 with constant pressureflows along the inner circumferential side wall 501 a (in the directionindicated by an arrow in the figure) to generate rotational flow in thefluid chamber 501. Bubbles having low density and contained in the fluidchamber 501 gather at the center of the rotational flow due tocentrifugal force of the rotational flow.

The bubbles gathered at the center are discharge through the outlet flowpath 511. Thus, it is preferable that the outlet flow path 511 isdisposed in the vicinity of the center of the rotational flow, that is,the axial center of the rotation body. According to the example shown inFIG. 4, the shape of the inlet flow path 503 in the plan view is curvedin spiral shape. The inlet flow path 503 may have a linear shapecommunicating with the fluid chamber 501, but is curved in thisembodiment so as to obtain desired inertance in the narrow space byincreasing the flow path length of the inlet flow path 503.

As illustrated in FIG. 2, the reinforcing plate 410 is provided betweenthe diaphragm 400 and the periphery of the sealing surface 505 on whichthe inlet flow path 503 is formed. The reinforcing plate 410 is providedfor the purpose of increasing durability of the diaphragm 400. Since anotch-shaped connection opening 509 is formed on the connecting portionbetween the inlet flow path 503 and the fluid chamber 501, it isconsidered that fatigue breakage is caused by stress concentration inthe vicinity of the connection opening 509 when the diaphragm 400 isoperated at high frequency. Thus, the reinforcing plate 410 havingcontinuous opening without notch is provided to prevent stressconcentration generated on the diaphragm 400.

According to the fluid ejection device 1 having this structure, thescrew holes 500 a are formed at the four corners of the outer peripheryof the upper case 500 such that the upper case 500 and the lower case301 can be connected with each other by screws inserted into the screwholes 500 a. However, the reinforcing plate 410 and the diaphragm 400may be connected and fixed to one another in lamination as one pieceunit, for example, though not shown in the figure. The reinforcing plate410 and the diaphragm 400 may be fixed by adhesive, fixed layer diffusedjunction, welding or other fixing methods. It is preferable that thereinforcing plate 410 and the diaphragm 400 are closely connected witheach other via the junction surface.

According to the fluid ejection device 1 having this structure, theoutlet flow path 511 and the nozzle 211 are connected with each othervia the connection flow path pipe 200. However, the nozzle 211 may beinserted into the end of the outlet flow path pipe 510 on the sideopposite to the fluid chamber 501 without using the connection flow pathpipe 200. In this case, the structure can be further simplified.

When the fluid ejection device 1 is used in operation, it is preferablethat the connection flow path pipe 200 is used so as to appropriatelyincrease the distance between a handpiece and the fluid ejection opening212 (to be a length capable of reaching a deeper affected part).

The principle of the fluid delivery performed by the pulse generatingunit 100 according to this embodiment is now discussed.

The fluid delivery by the pulse generating unit 100 in this embodimentis achieved by the difference between inlet flow path side inertance L1(referred to as synthetic inertance L1 as well) and outlet flow pathside inertance L2 (referred to as synthetic inertance L2 as well).

Initially, the details of inertance are explained.

Inertance L is expressed as L=ρ×h/S (ρ: density of fluid, S:cross-sectional area of flow path, h: length of flow path). Bytransforming the equation of motion in the flow path by using theinertance L, the relation ΔP=L×dQ/dt is obtained (ΔP: pressuredifference in flow path, Q: flow amount of fluid flowing in flow path).

Thus, the inertance L indicates effect level for flow amount change withtime. The flow amount change with time decreases as the inertance Lbecomes larger, but increases as the inertance L becomes smaller.

In case of synthetic inertance in parallel connection of plural flowpaths or in serial connection of plural flow paths having differentshapes, synthetic inertance can be calculated by combining inertance ofeach flow path similarly to inductance in parallel connection or serialconnection of electric circuit.

Since the diameter of the connection flow path 504 is sufficientlylarger than that of the inlet flow path 503, only the inertance of theinlet flow path 503 needs to be calculated as the inertance L1 on theinlet flow path side. Since the connection tube for connecting the pump20 and the inlet flow path and has flexibility, the inertance of theconnection tube is excluded from the calculation of the inertance L1.

The diameter of the connection flow path 201 is considerably larger thanthat of the outlet flow path, and the pipe portion (pipe wall) of theconnection flow pipe 200 has only a small effect on the inertance L2 onthe outlet flow path side when the thickness of the pipe portion of theconnection flow pipe 200 is small. Thus, the inertance L2 on the outletflow path side can be replaced with the inertance of the outlet flowpath 511.

When the thickness of the pipe wall of the connection flow path pipe 200is large, the inertance L2 becomes the synthesis inertance of the outletflow path 511, the connection flow path 201, and the nozzle 211.

In this embodiment, the flow path length and the cross-sectional area ofthe inlet flow path 503 and the flow path length and the cross-sectionalarea of the outlet flow path 511 are determined such that the inertanceL1 on the inlet flow path side becomes larger than the inertance L2 onthe outlet flow path side.

The detailed structure of the drive unit 30 is now described withreference to FIG. 5.

FIG. 5 is a block diagram showing the detailed structure of the driveunit 30.

As shown in FIG. 5, the drive unit 30 includes an operation controlsection 30 a, a first drive signal supplying section 30 b, a vibrationdetecting section 30 c, a data storing section 30 e, a second drivesignal supplying section 30 f, and a synchronous signal generatingsection 30 g.

The operation control section 30 a has function of issuing operationcommands to the respective components in response to operation inputgiven through an input unit (not shown) of the fluid ejection device 1.The operation control section 30 a provides function of controllingvarious operation processes such as process for supplying drive signalsfrom the first drive signal supplying section 30 b, process fordetermining contact condition of the nozzle 211, and process forsupplying drive signals from the second drive signal supplying section30 f.

More specifically, the operation control section 30 a outputs vibrationgenerating command which requests the connection flow path pipe 200 togenerate vibrating force for vibrating the nozzle 211 to the first drivesignal supplying section 30 b when the drive switch (not shown) of thewater pulse scalpel is switched to ON from OFF.

By this step, the piezoelectric element 50 expands and contracts inresponse to the drive signals supplied from the first drive signalsupplying section 30 b to produce vibrating force. Then, this vibratingforce is transmitted to the connection flow path 200 and the nozzle 211to vibrate the connection flow path pipe 200 and the nozzle 211.

The operation control section 30 a determines whether the nozzle 211contacts the affected portion or an object in the vicinity of theaffected portion (such as ejected fluid reservoir) based on thedetection result of the vibration level received from the vibrationdetecting section 30 c (output voltage of the distortion gauge 51) andthe threshold of the vibration level stored in the data storing section30 e. When it is determined that the nozzle 211 contacts the affectedportion or the object, the operation control section 30 a issuesejection driving command for performing fluid ejection to the seconddrive signal supplying section 30 f.

By this step, the second drive signal supplying section 30 f suppliesdrive signals to the piezoelectric element 401 to expand and contractthe piezoelectric element 401. Then, the fluid chamber 501 thuscontracted compresses fluid inside the fluid chamber 501 to generatepulsed flow to be ejected through the fluid ejection opening 212 via theoutput flow path 511 and the connection flow path 201.

When it is determined that the nozzle 211 does not contact the affectedportion or the object, the operation control section 30 a does notoutput ejection driving command or outputs ejection stop command duringejection of fluid (during operation of piezoelectric element 401).

When the drive switch of the water pulse scalpel is switched from ON toOFF, the operation control section 30 a issues ejection stop command forstopping fluid ejection to the second drive signal supplying section 30f. Then, the operation control section 30 a outputs vibration stopcommand for suspending vibration of the nozzle 211 to the first drivesignal supplying section 30 b.

By this step, fluid ejection and vibration of the nozzle 211 stop.

The first drive signal supplying section 30 b has function of supplyingdrive signals for generating vibration to the piezoelectric element 50in synchronization with synchronous signals from the synchronous signalgenerating section 30 g in response to vibration generating commandreceived from the operation control section 30 a.

More specifically, the first drive signal supplying section 30 b readscorresponding vibration generation waveform information (digitalwaveform data) from the data storing section 30 e based on waveformspecifying information contained in the vibration generating command,produces analog drive signals converted from the digital waveforminformation read from the data storing section 30 e, and supplies thedrive signals thus produced to the piezoelectric element 50 insynchronization with the synchronous signals. The waveform specifyinginformation is identification information or the like attached to thevibration generation signal waveform.

The first drive signal supplying section 30 b further has function ofstopping drive signal supply in response to the drive signal vibrationstop command received from the operation control section 30 a. Accordingto this embodiment, supply of drive signals is stopped after supply offinal waveform in one cycle being supplied to the piezoelectric element50 when the stop command is inputted from the operation control section30 a during supply of drive signals.

The vibration detecting section 30 c includes a detection circuit havingWheatstone bridge circuit to detect resistance change of the distortiongauge 51 resulting from bending change of the connection flow path pipe200 caused by vibrating force given from the piezoelectric element 50 asvoltage level by using the detection circuit. Then, the vibrationdetecting section 30 c outputs the detection level (voltage) as thedetection result to the operation control section 30 a.

The data storing section 30 e includes a storage medium for storingwaveform information about plural types of signal waveformscorresponding to the set ejection intensity and having different cyclesand amplitudes, thresholds for contact detection, data used forprocesses performed by the respective parts, and others. The datastoring section 30 e reads data stored in the storing medium in responseto reading requests from the respective parts, and writes the data tothe storing medium in response to writing requests from the respectiveparts.

The second drive signal supplying section 30 f has function of supplyingdrive signals to the piezoelectric element 401 of the capacity changingunit 405 through the supply lines JPZT(−) and JPZT(+) in synchronizationwith synchronous signals from the synchronous signal generating section30 g in response to the ejection driving command issued from theoperation control section 30 a.

More specifically, the second drive signal supplying section 30 f readscorresponding waveform information (digital waveform data) from the datastoring section 30 e based on waveform specifying information forejection drive contained in the ejection driving supply command,produces analog drive signals converted from the digital waveforminformation read from the data storing section 30 e, and supplies theproduced drive signals to the piezoelectric element 401 in synchronoussignals. The waveform specifying information is identificationinformation and the like attached to signal waveform for ejection drivecorresponding to ejection intensity.

The second drive signal supplying section 30 f further has function ofstopping drive signal supply in response to the ejection stop commandreceived from the operation control section 30 a. According to thisembodiment, supply of drive signals is stopped after supply of finalwaveform in one cycle being supplied to the piezoelectric element 401when stop command is inputted from the operation control section 30 aduring supply of drive signals.

The synchronous signal generating section 30 g includes an oscillatorsuch as ceramic oscillator and crystal oscillator, a counter (or PLLcircuit) and other components, and produces synchronous signals based onreference clock signals clk outputted from the oscillator. Thesynchronous signal generating section 30 g supplies the reference clocksignals and synchronous signals to the drive signal supplying section 30f.

The drive unit 30 has a computer system which provides functions of therespective sections described above by software and executes thesoftware for controlling hardware necessary for providing the functions.Though not shown in the figure, the hardware structure of this computersystem includes a processor, a RAM (random access memory), and a ROM(read only memory) connected with one another via various internal andexternal buses.

Furthermore, display device such as CRT and LCD monitor, and inputdevice such as operation panel, mouse, and keyboard are connected withthe buses via input/output interface (I/F) such as IEEE1394, USB, andparallel port.

When power is supplied, various computer programs dedicated forproviding the functions of the respective sections and stored in the ROMin advance are loaded into the RAM under the control of the systemprogram stored in the ROM or the like. Then, predetermined controls andcalculations are performed by the processor using various resourcesaccording to commands written in the programs loaded to the RAM toprovide the respective functions.

The attachment structure of the piezoelectric element 50 and thedistortion gauge 51 to the connection flow path pipe 200 is nowdiscussed with reference to FIGS. 6 and 7A through 7D.

FIG. 6 illustrates the attachment structure of the piezoelectric element50 and the distortion gauge 51 to the connection flow path pipe 200.FIGS. 7A through 7D illustrate other examples of the attachmentstructure of the piezoelectric element 50 and the distortion gauge 51 tothe connection flow path pipe 200.

As illustrated in FIG. 6, the piezoelectric element 50 and thedistortion gauge 51 are disposed and fixed to the outer circumferentialsurface of the connection flow path pipe 200 at positions closer to thepulse generating unit 100.

As can be seen from a cross-sectional view positioned in the lower partof FIG. 6 and taken along a line B-B′ in a circled portion in the upperpart of FIG. 6, the piezoelectric element 50 and the distortion gauge 51in this embodiment are fixed to the outer circumferential surface(curved surface) of the connection flow path pipe 200 having annularcross section.

Thus, attachment portions of the piezoelectric element 50 and thedistortion gauge 51 are so bended as to be closely fixed to the curvedouter circumferential surface of the connection flow path pipe 200.

The attachment structure of the piezoelectric element 50 and thedistortion gauge 51 is not limited to this structure, but may be astructure shown in FIG. 7A, for example. According to this structure, atleast the attachment portion of the connection flow path pipe 200 towhich the piezoelectric element 50 and the distortion gauge 51 areattached is formed in such a shape as to have a rectangular crosssection and thus have a horizontal surface on the outer circumferentialsurface. Then, the piezoelectric element 50 and the distortion gauge 51are disposed and fixed to the horizontal surface thus formed.

Alternatively, as illustrated in FIGS. 7B and 7C, the piezoelectricelement 50 and the distortion gauge 51 may be disposed and fixed to ahorizontal surface formed only on the portion of the connection flowpath pipe 200 for attachment with the piezoelectric element 50 and thedistortion gauge 51 as the surface produced by pressing and crushing thecurved surface of the attachment portion having annular cross section orby other method.

Alternatively, as illustrated in FIG. 7D, the piezoelectric element 50and the distortion gauge 51 may be disposed and fixed to a horizontalsurface corresponding to the portion of the connection flow path pipe200 for attachment with the piezoelectric element 50 and the distortiongauge 51 as a surface formed on the outer peripheral surface of theouter pipe wall portion having rectangular cross section with the innerhollow portion of the connection flow path pipe 200 having circularcross section.

According to the attachment structures shown in FIGS. 7A through 7D, thenecessity for bending the piezoelectric element 50 and the distortiongauge 51 is eliminated by forming the horizontal surface on the outerperipheral surface of the pipe and fixing the piezoelectric element 50and the distortion gauge 51 to the horizontal surface. Thus, attachmentof the piezoelectric element 50 and the distortion gauge 51 can beeasily achieved. These attachment structures are effective particularlyfor piezoelectric element of a type difficult to be bended.

The flow of operation control process for controlling the first drivesignal supplying section 30 b and the second drive signal supplyingsection 30 f performed by the operation control section 30 a is nowdiscussed with reference to FIG. 8.

FIG. 8 is a flowchart showing the operation control process forcontrolling the first drive signal supplying section 30 b and the seconddrive signal supplying section 30 f performed by the operation controlsection 30 a.

When the operation control process is initiated under the dedicatedprogram executed by the processor, the flow goes to step S100 as shownin FIG. 8.

In step S100, the operation control section 30 a determines whether thedrive switch of the water pulse scalpel (hereinafter abbreviated as WPS)is turned on. When it is determined that the drive switch is ON (YES),the flow goes to step S102. When it is determined that the drive switchis not ON (NO), the process is repeated until the drive switch is turnedon.

When the flow goes to step S102, the operation control section 30 aoutputs vibration generating command to the first drive signal supplyingsection 30 b. Then, the flow goes to step S104.

In step S104, the operation control section 30 a compares the detectedvoltage received from the vibration detecting section 30 c and thethreshold for contact detection stored in the data storing section 30 e.Then, the flow goes to step S106.

The comparison in this step may be comparison between the threshold andthe detected voltage (absolute value), comparison between the thresholdand the average value of the detected voltages (absolute values) for apredetermined period, or other comparison.

According to this embodiment, the average voltage is calculated as inthe latter method, and the calculated average is compared with athreshold indicating the average of voltages measured in advance whenvibration is weakened by contact between the nozzle 211 and the affectedportion, the object in the vicinity of the affected portion or the like.

In step S106, the operation control section 30 a determines whether theaverage of the detected voltages for the predetermined period is equalto or lower than the threshold or not based on the comparison result instep S104. When it is determined that the average is the threshold orlower (YES), the flow goes to step S108. When it is determined that theaverage is not the threshold or lower (NO), the flow goes to step S116.

When the flow goes to step S108, the operation control section 30 adetermines that the nozzle 211 contacts the affected portion or theobject in the vicinity of the affected portion and outputs ejectiondriving command to the second drive signal supplying section 30 f. Then,the flow goes to step S110.

In step S110, the operation control section 30 a determines whether thedrive switch is turned off. When it is determined that the drive switchis off (YES), the flow goes to step S112. When it is determined that thedrive switch is not off (NO), the flow goes to step S104.

When the flow goes to step S112, the operation control section 30 aoutputs ejection stop command to the second drive signal supplyingsection 30 f. Then, the flow goes to step S114.

When the flow goes to step S114, the operation control section 30 aoutputs vibration stop command to the first drive signal supplyingsection 30 b. Then, the flow goes to step S104.

When the flow goes to step S116 by determination that the nozzle 211 isnot under contact condition based on the average of the detectedvoltages for the predetermined period higher than the threshold, theoperation control section 30 a outputs ejection stop command to thesecond drive signal supplying section 30 f. Then, the flow goes to stepS100. When ejection is not under operation, the flow may go to step S100without outputting ejection stop command.

The flow of process for supplying drive signals to the piezoelectricelement 50 performed by the first drive signal supplying section 30 b isnow discussed with reference to FIG. 9.

FIG. 9 is a flowchart showing the drive signal supply process performedby the first drive signal supplying section 30 b.

When the process for supplying drive signals to the piezoelectricelement 50 is initiated under the dedicated program executed by theprocessor, the flow goes to step S200 as shown in FIG. 9.

In step S200, the first drive signal supplying section 30 b determineswhether vibration generating command is inputted from the operationcontrol section 30 a. When it is determined that the vibrationgenerating command is inputted (YES), the flow goes to step S202. Whenit is determined that the vibration generating command is not inputted(NO), the determining process is repeated until the command is inputted.

When the flow goes to step S202, the first drive signal supplyingsection 30 b reads vibration generation waveform data used for drivingthe piezoelectric element 50 from the data storing section 30 e based onthe identification information of the specified waveform contained inthe vibration generating command. Then, the flow goes to step S204.

In step S204, the first drive signal supplying section 30 b converts thedigital waveform signals of the waveform data read in step S202 intoanalog waveform signals. Then, the flow goes to step S206.

In step S206, the first drive signal supplying section 30 b outputsdrive signals having the analog signal waveform obtained by D/Aconversion in step S204 to the piezoelectric element 50 insynchronization with synchronous signals from the synchronous signalgenerating section 30 g. Then, the flow goes to step S208.

In step S208, the first drive signal supplying section 30 b determineswhether vibration stop command is inputted from the operation controlsection 30 a. When it is determined that the vibration stop command isinputted (YES), the flow goes to step S210. When it is determined thatthe vibration stop command is not inputted (NO), the drive signal outputprocess in step S204 is continued.

When the flow goes to step S210, the first drive signal supplyingsection 30 b stops drive signal supply after output of all signals inone cycle. Then, the flow goes to step S200.

The flow of process for supplying drive signals to the piezoelectricelement 401 performed by the second drive signal supplying section 30 fis now discussed with reference to FIG. 10.

FIG. 10 is a flowchart showing the drive signal supply process performedby the second drive signal supplying section 30 f.

When the process for supplying drive signals to the piezoelectricelement 401 is initiated under the dedicated program executed by theprocessor, the flow goes to step S300 as shown in FIG. 10.

In step S300, the second drive signal supplying section 30 f determineswhether ejection driving command is inputted to the operation controlsection 30 a. When it is determined that the ejection driving command isinputted (YES), the flow goes to step S302. When it is determined thatthe ejection driving command is not inputted (NO), the determiningprocess is repeated until the command is inputted.

When the flow goes to step S302, the second drive signal supplyingsection 30 f reads ejection drive waveform data used for driving thepiezoelectric element 401 from the data storing section 30 e based onthe identification information of the specified waveform contained inthe ejection driving command. Then, the flow goes to step S304.

In step S304, the second drive signal supplying section 30 f convertsdigital waveform signals having the waveform data read in step S302 intoanalog waveform signals. Then, the flow goes to step S306.

In step S306, the second drive signal supplying section 30 f outputsdrive signals having the analog signal waveform obtained by D/Aconversion in step S304 to the piezoelectric element 401 insynchronization with synchronous signals from the synchronous signalgenerating section 30 g. Then, the flow goes to step S308.

In step S308, the second drive signal supplying section 30 f determineswhether the ejection stop command is inputted from the operation controlsection 30 a. When it is determined that the ejection stop command isinputted (YES), the flow goes to step S310. When it is determined thatthe ejection stop command is not been inputted (NO), the drive signaloutput process in step S304 is continued.

When the flow goes to step S310, the second drive signal supplyingsection 30 f stops drive signal supply after output of all signals inone cycle. Then, the flow goes to step S300.

The specific operation of the fluid ejection device 1 in this embodimentis herein described with reference to FIG. 11.

FIG. 11 shows an example of vibration waveform during contact and noncontact of the nozzle 211.

When the power source of the fluid ejection device 1 is turned on,initialization operation is performed. Then, the process proceeds todrive standby condition.

When the drive switch of the WPS is turned on under this condition(“YES” branch in step S100), the operation control section 30 a outputsvibration generating command to the first drive signal supplying section30 b (step S102).

When receiving the vibration generating command from the operationcontrol section 30 a (“YES” branch in step S200), the first drive signalsupplying section 30 b reads vibration generation waveform data from thedata storing section 30 e and supplies the vibration generation waveformdata to the work memory such as RAM. Then, the first drive signalsupplying section 30 b converts the read digital waveform data intoanalog waveform signals (step S204).

Subsequently, the first drive signal supplying section 30 b outputs theanalog vibration generation waveform signals thus produced to thepiezoelectric element 50 in synchronization with synchronous signalsfrom the synchronous signal generating section 30 g (step S206).

By this step, the piezoelectric element 50 expands and contracts toproduce expanding and contracting force (vibrating force). Thisvibrating force is transmitted to the connection flow path pipe 200 viathe attachment portion to bend the connection flow path pipe 200 in thedirection of applying the force thereto. The connection flow path pipe200 and the nozzle 211 vibrate by the bending force and restoring forcefrom the bended condition. In this case, larger vibration can begenerated from smaller force by driving the piezoelectric element 50such that the applied vibrating force has the natural frequency of theconnection flow path pipe 200.

The deformation of the connection flow path pipe 200 caused by thevibration transmits distortion to an inside resistor (line and foil)through a base (attachment portion) of the distortion gauge 51. Thevibration detecting section 30 c detects resistance change correspondingto the produced distortion in the detection circuit as voltage, andoutputs the detected voltage to the operation control section 30 a.

Under non-contact condition of the nozzle 211 with the affected portion,the object in the vicinity of the affected portion or the like, thevibration produced on the nozzle 211 has an amplitude shown in the leftpart of FIG. 11 larger than the amplitude of the waveform at the time ofcontact of the nozzle 211 shown in the right part of FIG. 11 at thevibration detecting section 30 c.

This is because vibration is weakened by the contact between the nozzle211 and the affected portion, the object in the vicinity of the affectedportion or the like.

The operation control section 30 a calculates the average of theabsolute values of the detected voltages for the predetermined period,and compares the average with the threshold stored in the data storingsection 30 e (step S104).

Then, the operation control section 30 a outputs ejection drivingcommand to the second drive signal supplying section 30 f based on thecomparison determination that the nozzle 211 contacts the affectedportion or the object in the vicinity of the affected portion when theaverage is the threshold or lower (“YES” branch in step S106) (stepS108).

When the average is higher than the threshold (“NO” branch in stepS106), the operation control section 30 a does not output the ejectiondriving command to the second drive signal supplying section 30 f basedon the determination that the nozzle 211 does not contact the affectedportion or the object in the vicinity of the affected portion even underthe ON condition of the drive switch (step S116).

When receiving the ejection driving command from the operation controlsection 30 a (“YES” branch in step S300), the second drive signalsupplying section 30 f reads the corresponding ejection drive waveformdata from the data storing section 30 e based on the identificationinformation of the waveform information contained in the ejectiondriving command, and supplies the ejection drive waveform data to thework memory such as RAM (step S302).

Then, the digital waveform data supplied to the work memory is convertedto analog data to produce analog drive signals (step S304).

Subsequently, the second drive signal supplying section 30 f outputs theanalog drive signals for ejection drive thus produced to thepiezoelectric element 401 in synchronization with the synchronous signalgenerating section 30 g (step S306).

In this case, fluid is kept supplied to the inlet flow path 503 withconstant liquid pressure by using the pump 20 before drive signals aresupplied. Thus, fluid flows into the fluid chamber 501 by the differencebetween the delivering force of the pump 20 and the fluid resistance ofthe entire inlet flow path when the piezoelectric element 401 does notoperate.

When the piezoelectric element 401 rapidly expands in response to adrive signal inputted to the piezoelectric element 401, the pressureinside the fluid chamber 501 rapidly increases to several tens of atms.under the condition of sufficient inertances L1 and L2 on the inlet flowpath side and the outlet flow path side.

This pressure is considerably higher than the pressure applied to theinlet flow path 503 by the pump 20. Thus, the flow amount of the fluidfrom the inlet flow path side into the fluid chamber 501 decreases, andthe flow amount of the fluid discharged from the outlet flow path 511increases due to the high pressure.

However, the inertance L1 of the inlet flow path 503 is larger than theinertance L2 of the outlet flow path 511. In this case, the increaseamount of the fluid discharged from the outlet flow path becomes largerthan the decrease amount of the fluid flowing from the inlet flow path503 into the fluid chamber 501. Thus, pulsed fluid delivery, that is,pulsed flow is produced in the connection flow path 201. The pressurechange at the time of delivery is transmitted through the connectionflow path pipe 200, and fluid is ejected from the fluid ejection opening212 at the end of the nozzle 211.

The diameter of the fluid ejection opening 212 of the nozzle 211 issmaller than that of the outlet flow path 511. Thus, fluid is ejected ashigh-speed pulsed liquid drops.

The inside of the fluid chamber 501 is brought into vacuum conditionimmediately after pressure increase by interaction of the decrease inthe fluid flow-in amount from the inlet flow path 503 and the increasein the fluid discharge amount from the outlet flow path 511.

Then, the expanded piezoelectric element 401 comes to contract at aspeed corresponding to the falling shape of the drive waveform, and theflow of fluid finally returns to the steady condition before supply ofthe drive signals.

In this structure, the fluid chamber 501 has a substantially rotationalbody and the inlet flow path 503, and the outlet flow path 511 is formedin the vicinity of the rotation axis of the substantially rotationalbody of the fluid chamber 501. Thus, rotational flow is generated withinthe fluid chamber 501, and bubbles (vacuum bubbles and gas bubbles)contained in the fluid are rapidly discharged from the outlet flow path511 to the outside.

The pulsed flow can be continuously ejected from the nozzle 211 bysuccessively supplying drive signals to the piezoelectric element 401.

When the operator moves the pulse generating unit 100 and separates thenozzle 211 from the affected portion or the object in the vicinity ofthe affected portion under the condition in which pulsed flow iscontinuously ejected in response to successive supply of drive signals,thereby removing any factor for preventing vibration of the nozzle 211,the voltage detected by the vibration detecting section 30 c increases.

By this step, the average of the absolute values of the detectedvoltages for the predetermined period becomes higher than the threshold(“NO” branch in step S106). Then, the operation control section 30 aoutputs ejection stop command to the second drive signal supplyingsection 30 f based on determination that the nozzle 211 does not contactthe affected portion or the object in the vicinity of the affectedobject (step S116).

When receiving the ejection stop command from the operation controlsection 30 a (“YES” branch in step S308), the second drive signalsupplying section 30 f stops drive signal supply after supply of alldrive signals currently supplied in one cycle (step S310).

When the nozzle 211 again contacts the affected portion or the object inthe vicinity of the affected portion under the ON condition of the driveswitch of the WPS, the vibration of the nozzle 211 is weakened. As aresult, the voltage detected by the vibration detecting section 30 cdecreases.

By this step, the average of the absolute values of the detectedvoltages for the predetermined period becomes the threshold or lower(“YES” branch in step S106). Then, the operation control section 30 aoutputs ejection driving command to the second drive signal supplyingsection 30 f based on determination that the nozzle 211 contacts theaffected portion or the object in the vicinity of the affected portion(step S108). By this step, drive signals are supplied to thepiezoelectric element 401, and ejection of pulsed flow is restarted.

When the drive switch of the WPS is turned off by the operator underthis condition, the operation control section 30 a determines that thedrive switch has been turned off (“YES” branch in step S110). Then, theoperation control section 30 a outputs ejection stop command to thesecond drive signal supplying section 30 f (step S112).

By this step, the second drive signal supplying section 30 f stops drivesignal supply after supplying of all drive signals currently supplied inone cycle (step S310). By suspension of drive signal supply, ejection ofthe pulsed flow stops accordingly.

Then, the operation control section 30 a outputs vibration stop commandto the first drive signal supplying section 30 b (step S114).

By this step, the first drive signal supplying section 30 b stops drivesignal supply after supply of all drive signals currently supplied inone cycle (step S210). By suspension of drive signal supply, vibrationstops accordingly.

According to the fluid ejection device 1 in this embodiment, the firstdrive signal supplying section 30 b drives the vibration generatingpiezoelectric element 50 to vibrate the nozzle 211 when the drive switchof the WPS is ON. Moreover, the vibration detecting section 30 c detectsthe level of the vibration, and the operation control section 30 adetermines whether the nozzle 211 contacts the affected portion or thelike based on the detection result. When it is determined that thenozzle 211 contacts the affected portion or the like, the operationcontrol section 30 a outputs ejection driving command to the seconddrive signal supplying section 30 f. The second drive signal supplyingsection 30 f supplies drive signals to the capacity changingpiezoelectric element 401 in response to ejection driving command tochange the capacity of the fluid chamber 501 and perform ejection offluid.

When it is determined that the nozzle 211 does not contact the affectedportion or the like, the operation control section 30 a outputs ejectionstop command to the second drive signal supplying section 30 f.

The second drive signal supplying section 30 f stops drive signal supplyto the capacity changing piezoelectric element 401 in response to theejection stop command to stop ejection of fluid.

The operation control section 30 a does not output ejection drivingcommand to the second drive signal supplying section 30 f while ejectionof fluid is not performed under the ON condition of the drive switch ofthe WPS.

By this method, ejection is suspended when the nozzle 211 does notcontact the affected portion or the like. Thus, ejection of pulsed flowin an unexpected direction (such as direction toward eyes of a doctor ora nurse in the operation room and a portion not desired to be removed)and scattering of tissue pieces cut by the ejection in an unexpecteddirection or position can be prevented when the nozzle 211 is separatedfrom the affected portion or the object in the vicinity of the affectedportion (such as liquid reservoir of ejected fluid or blood) byoperation error of the operator (doctor in charge).

According to the first embodiment, the nozzle 211 and the fluid ejectionopening 212 correspond to a fluid ejection opening as referred to in anyof the first, second, fourth and fourteenth aspects. The capacitychanging section 405 and the second drive signal supplying section 30 fcorrespond to a capacity changing unit as referred to in any of thefirst, thirteenth and fourteenth aspects. The fluid container 10 and thepump 20 correspond to a fluid supplying unit as referred to in any ofthe first and fourteenth aspects. The piezoelectric element 50 and thefirst drive signal supplying section 30 b correspond to a vibrating unitas referred to in any of the first, fourth and fourteenth aspects. Thedistortion gauge 51 and the vibration detecting section 30 c correspondto a vibration detecting unit as referred to in any of the first,fourth, thirteenth and fourteenth aspects. The operation control section30 a corresponds to an operation control unit as referred to in any ofthe first, thirteenth and fourteenth aspects. The piezoelectric element50 corresponds to a vibrating force generating section as referred to inany of the fourth, fifth and ninth aspects. The distortion gauge 51corresponds to a vibration receiving section as referred to in any ofthe fourth, fifth and eighth aspects.

Second Embodiment

A second embodiment according to an aspect of the invention ishereinafter described. FIGS. 12 through 14 show a fluid ejection device,a driving method of a fluid ejection device, and an operating instrumentaccording to the second embodiment of an aspect of the invention.

The second embodiment is different from the first embodiment in thatcomponents such as a suction pipe and a pump disposed in such positionsas to cover the connection flow path pipe 200 are equipped to suck anobject close to the nozzle 211 and give sucking force, respectively, andthat the vibration generating piezoelectric element 50 and thedistortion gauge 51 are provided on the outer circumferential surface ofthe suction pipe. Other parts are similar to those of the firstembodiment. In the following description, only the different parts arediscussed in detail. Similar reference numerals are given to similarparts, and explanation of the similar parts is not repeated.

The structure of the fluid ejection device according to this embodimentis now described with reference to FIG. 12. FIG. 12 illustrates ageneral structure of a fluid ejection device 3 according to thisembodiment.

As illustrated in FIG. 12, the fluid ejection device 3 has a basicstructure including the fluid container 10 for storing fluid, the pump20 as a pressure generating unit, a suction container 70 for storingsucked object, a suction pump 60 as sucking force giving unit, the pulsegenerating unit 100 for generating pulsed flow of fluid supplied fromthe pump 20, the drive unit 30 for driving the pulse generating unit100, the vibration generating piezoelectric element 50, and thedistortion gauge 51.

The pulse generating unit 100 is connected with the connection fluidpath pipe 200 having narrow pipe shape. The nozzle 211 having a diametersmaller than the flow path diameter of the connection flow path pipe 200is inserted into the end of the connection flow path pipe 200.

A pipe-shaped suction pipe 700 having a diameter larger than that of theconnection flow path pipe 200 and containing the connection flow pathpipe 200 is connected with the pulse generating unit 100.

A passage through which sucked object such as delivered liquid andtissue pieces passes is formed between the inner circumferential surfaceof the suction pipe 700 and an outer circumferential surface of theconnection flow path pipe 200 having a different diameter from that ofthe suction pipe 700.

An outlet flow path pipe 702 through which the sucked object is suppliedto the suction container 70 projects from the suction pipe 700 on thepulse generating unit 100 side. The sucked object is attracted by thesuction pump 60 via a connection tube 65 connected with the outlet flowpath pipe 702, and discharged toward the suction container 70 via aconnection tube 75.

Passages along which two supply lines VPZT(−) and VPZT(+) for supplyingdrive signals to the piezoelectric element 50, gauge input line andgauge output line for the distortion gauge 51, and two supply linesJPZT(−) and JPZT(+) for supplying drive signals to the fluid ejectingpiezoelectric element 401 (described later) are wired are formed insidethe pulse generating unit 100.

These passages are joined at the exit of the signal lines extending fromthe pulse generating unit 100, and the four supply lines and the gaugeinput line and gauge output line collected at one position of the exitextend to the outside.

These lines are collected by a cable 47 and connected with the driveunit 30. The respective lines of the cable 47 are electrically connectedwith the corresponding components of the drive unit 30.

The attachment structure of the piezoelectric element 50 and thedistortion gauge 51 to the suction pipe 700 is now explained withreference to FIG. 13 and FIGS. 14A through 14D.

FIG. 13 illustrates the attachment structure of the piezoelectricelement 50 and the distortion gauge 51 to the suction pipe 700. FIGS.14A through 14D show other examples of the attachment structure of thepiezoelectric element 50 and the distortion gauge 51 to the suction pipe700.

As illustrated in FIG. 13, the piezoelectric element 50 and thedistortion gauge 51 in this embodiment are disposed and fixed to theouter circumferential surface of the suction pipe 700 at positionscloser to the pulse generating unit 100.

Also, the piezoelectric element 50 and the distortion gauge 51 are fixedto the circumferential surface (curved surface) having annular crosssection as shown in a cross-sectional view positioned in the lower partof FIG. 13 corresponding to a portion circled and taken along a lineC-C′ in the upper part of FIG. 13.

Thus, attachment portions of the piezoelectric element 50 and thedistortion gauge 51 are so bended as to be closely fixed to the curvedouter circumferential surface of the suction pipe 700.

The attachment structure of the piezoelectric element 50 and thedistortion gauge 51 is not limited to this structure, but may be astructure shown in FIG. 14A, for example. According to this structure,at least the attachment portion of the suction pipe 700 to which thepiezoelectric element 50 and the distortion gauge 51 are attached isformed in such a shape as to have a rectangular cross section and thushave a horizontal surface on the outer circumferential surface. Then,the piezoelectric element 50 and the distortion gauge 51 are disposedand fixed to the horizontal surface thus formed.

Alternatively, as illustrated in FIGS. 14B and 14C, the piezoelectricelement 50 and the distortion gauge 51 may be disposed and fixed to ahorizontal surface formed only on the portion of the suction pipe 700for attachment with the piezoelectric element 50 and the distortiongauge 51 as the surface produced by pressing and crushing the curvedsurface of the attachment portion having annular cross section or byother method.

Alternatively, as illustrated in FIG. 14D, the piezoelectric element 50and the distortion gauge 51 may be disposed and fixed to a horizontalsurface corresponding to the portion for attachment with thepiezoelectric element 50 and the distortion gauge 51 as a surface formedon the outer peripheral surface of the outer pipe wall portion havingrectangular cross section with the inner hollow portion of the suctionpipe 700 having circular cross section.

According to the attachment structures shown in FIGS. 14A through 14D,the necessity for bending the piezoelectric element 50 and thedistortion gauge 51 is eliminated by forming the horizontal surface onthe outer peripheral surface of the pipe and fixing the piezoelectricelement 50 and the distortion gauge 51 to the horizontal surface. Thus,attachment of the piezoelectric element 50 and the distortion gauge 51can be easily achieved. These attachment structures are effectiveparticularly for piezoelectric element of a type difficult to be bended.

When the piezoelectric element 50 expands and contracts in response todrive signals for vibration generation supplied from the first drivesignal supplying section 30 b in this structure, this expanding andcontracting force (vibrating force) is transmitted to the suction pipe700 via the attachment portion to bend the suction pipe 700 in thedirection of applying the force thereto. The suction pipe 700 vibratesby the bending force and restoring force from the bended condition. Inthis case, larger vibration can be generated from smaller force bydriving the piezoelectric element 50 such that the applied vibratingforce has the natural frequency of the suction pipe 700.

The deformation of the suction pipe 700 caused by the vibrationtransmits distortion to an inside resistor (line and foil) through abase (attachment portion) of the distortion gauge 51. The vibrationdetecting section 30 c detects resistance change corresponding to theproduced distortion in the detection circuit as detected voltage, andoutputs the detected voltage to the operation control section 30 a.

Under non-contact condition of the end of the suction pipe 700 with theaffected portion, the object in the vicinity of the affected portion orthe like, the vibration produced on the suction pipe 700 has anamplitude shown in the left part of FIG. 11 larger than the amplitude ofthe waveform at the time of contact of the suction pipe 700 shown in theright part of FIG. 11 at the vibration detecting section 30 c similarlyto the first embodiment.

This is because vibration is weakened by the contact between the end ofthe suction pipe 700 such as the opening and the affected portion, theobject in the vicinity of the affected portion or the like.

When the drive switch of the WPS is turned on with the end of thesuction pipe 700 contacting with the affected portion, the object in thevicinity of the affected portion or the like, the average of theabsolute values of the detected voltages becomes the threshold or lower.Thus, the operation control section 30 a detects contact condition, andoutputs ejection driving command to the second drive signal supplyingsection 30 f.

By this step, the piezoelectric element 401 of the capacity changingsection 405 operates to eject high-pressure fluid (pulsed flow).

When the end of the suction pipe 700 is separated from the affectedportion or the object in the vicinity of the affected portion, theaverage of the absolute values of the detected voltages becomes largerthan the threshold. Thus, the operation control section 30 a detectsnon-contact condition and does not output ejection driving command tothe second signal supplying section 30 f even in the ON condition of thedrive switch.

While ejection is being performed under this condition, the operationcontrol section 30 a outputs ejection stop command to the second drivesignal supplying section 30 f. By this step, driving of thepiezoelectric element 401 of the capacity changing unit 405 stops, andejection of fluid (pulsed flow) stops accordingly.

The operation of the drive unit 30 is similar to that of the firstembodiment except that the target to be vibrated is not the nozzle 211and the connection flow pipe 200 but the suction pipe 700.

According to the fluid ejection device 3 in this embodiment, the firstdrive signal supplying section 30 b drives the vibration generatingpiezoelectric element 50 to vibrate the suction pipe 700 when the driveswitch of the WPS is ON. Also, the vibration detecting section 30 cdetects the level of the vibration, and the operation control section 30a determines whether the opening or other end portion of the suctionpipe 700 contacts the affected portion or the like based on thedetection result. When it is determined that the end of the suction pipe700 contacts the affected portion or the like, the operation controlsection 30 a outputs ejection driving command to the second drive signalsupplying section 30 f. The second drive signal supplying section 30 fsupplies drive signals to the capacity changing piezoelectric element401 in response to ejection driving command to change the capacity ofthe fluid chamber 501 and perform ejection of fluid.

When it is determined that the end of the suction pipe 700 does notcontact the affected portion or the like, the operation control section30 a outputs ejection stop command to the second drive signal supplyingsection 30 f.

The second drive signal supplying section 30 f stops drive signal supplyto the capacity changing piezoelectric element 401 in response to theejection stop command to stop ejection of fluid.

The operation control section 30 a does not output ejection drivingcommand to the second drive signal supplying section 30 f while ejectionof fluid is not performed under the ON condition of the drive switch ofthe WPS.

By this method, ejection operation is suspended when the end of thesuction pipe 700 and the nozzle 211 do not contact the affected portionor the like. Thus, ejection of pulsed flow in an unexpected direction(such as direction toward eyes of a doctor or a nurse in the operationroom and a portion not desired to be removed) and scattering of tissuepieces cut by the ejection in an unexpected direction or position can beprevented when the nozzle 211 and the end of the suction pipe 700 areseparated from the affected portion or the object in the vicinity of theaffected portion (such as liquid reservoir of ejected fluid or blood) byoperation error of the operator (doctor in charge).

According to the second embodiment, the nozzle 211 and the fluidejection opening 212 correspond to a fluid ejection opening as referredto in any of the third and fourth aspects. The capacity changing section405 and the second drive signal supplying section 30 f correspond to acapacity changing unit as referred to in any of the third and thirteenthaspects. The fluid container 10 and the pump 20 correspond to a fluidsupplying unit as referred to the third aspect. The suction pipe 700corresponds to a suction pipe as referred to in any of the third, sixthand seventh aspects. The suction pump 60 corresponds to a sucking forcegiving unit as referred to in the third aspect. The piezoelectricelement 50 and the first drive signal supplying section 30 b correspondto a vibrating unit as referred to in any of the third and fourthaspects. The distortion gauge 51 and the vibration detecting section 30c correspond to a vibration detecting unit as referred to in any of thethird, fourth and thirteenth aspects. The operation control section 30 acorresponds to an operation control unit as referred to in any of thethird and thirteenth aspects. The piezoelectric element 50 correspondsto a vibrating force generating section as referred to in any of thesixth, seventh and ninth aspects. The distortion gauge 51 corresponds toa vibration receiving section as referred to in any of the sixth,seventh and eighth aspects.

Third Embodiment

A third embodiment according to an aspect of the invention ishereinafter described. FIGS. 15A through 17B show a fluid ejectiondevice, a driving method of a fluid ejection device, and an operatinginstrument according to the third embodiment of an aspect of theinvention.

The third embodiment is different from the first and second embodimentsin that application of vibrating force to the connection flow path pipe200 or the suction pipe 700 and detection of the level of vibration areachieved by time divisions using a single piezoelectric element providedon the connection flow path pipe 200 or the suction pipe 700. Thus, apart of the drive unit 30 is different from the drive unit 30 of thefirst and second embodiments. Other parts are similar to those of thefirst and second embodiments. In the following description, only thedifferent parts are discussed in detail. Similar reference numerals aregiven to similar parts, and explanation of the similar parts is notrepeated.

The attachment structure of a piezoelectric element 52 having bothfunctions of giving vibrating force and receiving vibration in thisembodiment is initially described with reference to FIGS. 15A and 15B.

FIG. 15A shows an example of the attachment structure of thepiezoelectric element 52 to the connection flow path pipe 200. FIG. 15Bshows an example of the attachment structure of the piezoelectricelement 52 to the suction pipe 700.

According to this embodiment, application of vibrating force anddetection of the level of vibration are achieved by the singlepiezoelectric element 52. Thus, the distortion gauge 51 employed in thefirst and second embodiments can be eliminated.

In case of the fluid ejection device 1 having no suction pipe, thesingle piezoelectric element 52 is disposed and fixed to the outercircumferential surface of the connection flow path pipe 200 at aposition shifted toward the nozzle 211 from the outlet flow path pipe510 similarly to the piezoelectric element 50 in the first embodiment asillustrated in FIG. 15A.

The attachment structure of the piezoelectric element 52 may be any ofthe attachment structure of the piezoelectric element 50 shown in FIG. 6and the structures shown in FIGS. 7A through 7D in the first embodiment.

In case of the fluid ejection device 3 having the suction pipe, thesingle piezoelectric element 52 is disposed and fixed to the outercircumferential surface of the suction pipe 700 at a position closer tothe pulse generating unit 100 similarly to the piezoelectric element 50in the second embodiment as illustrated in FIG. 15B.

The attachment structure of the piezoelectric element 52 may be any ofthe attachment structure of the piezoelectric element 50 shown in FIG.13 and the structures shown in FIGS. 14A through 14D in the secondembodiment.

The detailed structure of a drive unit 30′ of the fluid ejection device1 or 3 including the single piezoelectric element 52 for givingvibrating force and receiving vibration in this embodiment is nowdiscussed with reference to FIG. 16.

FIG. 16 is a block diagram showing the detailed structure of the driveunit 30′ according to this embodiment.

As shown in FIG. 16, the drive unit 30′ includes the operation controlsection 30 a, the first drive signal supplying section 30 b, a vibrationdetecting unit 30 h, a connection switching section 30 d, the datastoring section 30 e, the second drive signal supplying section 30 f,and the synchronous signal generating section 30 g.

The operation control section 30 a has function of issuing operationcommands to the respective components in response to operation inputreceived from the input device of the fluid ejection device 1 or 3. Morespecifically, the operation control section 30 a has function ofcontrolling various operation processes such as supplying drive signalsfrom the first drive signal supplying section 30 b, switching timedivisions performed by the connection switching section 30 d,determining contact condition of the nozzle 211 or the end of thesuction pipe 700, and supplying drive signals from the second drivesignal supplying section 30 f based on the determination result.

The connection switching section 30 d switches between the electricconnection between the supply lines VPZT(−) and VPZT(+) of thepiezoelectric element 52 and the vibration detecting section 30 h, andthe electric connection between the supply lines VPZT(−) and VPZT(+) andthe first drive signal supplying section 30 b in response to controlsignals from the operation control section 30 a.

The connection may be switched by using a mechanical switch or switchingelements such as transistors.

The vibration detecting section 30 h detects electromotive forcegenerated on the piezoelectric element 52 by piezoelectric effect causedby vibration of the connection flow path pipe 200 or the suction pipe700, and outputs the electromotive force to the operation controlsection 30 a as detected voltage.

The operation of the drive unit 30′ according to this embodiment is nowexplained with reference to FIGS. 17A and 17B.

FIG. 17A shows vibration waveform for a period during which vibratingforce is given by the piezoelectric element 52. FIG. 17B shows vibrationwaveform for a period during which vibration is received by thepiezoelectric element 52.

The drive unit 30′ applies vibrating force and receives vibrationgenerated by the applied vibrating force (conversion from vibrationlevel to voltage by piezoelectric effect in this embodiment) by usingthe single piezoelectric element 52. When the drive switch of the WPS isturned on, the drive unit 30′ controls the operation of the connectionswitching section 30 d and the operation of the first drive signalsupplying section 30 b such that the process for supplying drive signalsto the piezoelectric element 52 from the first drive signal supplyingsection 30 b for a given period and the process for detecting the levelof vibration by the vibration detecting section 30 h for a given periodcan be alternately repeated by time division.

More specifically, when the drive switch is turned on, the operationcontrol section 30 a alternately switches between the electricconnection between the supply lines VPZT(−) and VPZT(+) of thepiezoelectric element 52 and the first drive signal supplying section 30b and the electric connection between the supply lines VPZT(−) andVPZT(+) of the piezoelectric element 52 and the vibration detectingsection 30 h by time division by controlling supply contents of controlsignals given to the connection switching section 30 d.

Simultaneously, the operation control section 30 a outputs vibrationgenerating command to the first drive signal supplying section 30 b atthe time of outputting the control signals to the connection switchingsection 30 d. By this step, the supply lines VPZT(−) and VPZT(+) of thepiezoelectric element 52 are electrically connected with the first drivesignal supplying section 30 b, and the vibration generating command issupplied to the first drive signal supplying section 30 b.

When receiving the vibration generating command from the operationcontrol section 30 a, the first drive signal supplying section 30 breads vibration generation waveform data from the data storing section30 e and supplies the data to the work memory such as RAM. Then, thefirst drive signal supplying section 30 b converts the digital waveformdata read from the data storing section 30 e into analog waveformsignals.

Subsequently, the first drive signal supplying section 30 b outputs thedrive signals for vibration generation thus generated to thepiezoelectric element 52 in synchronization with synchronous signalsfrom the synchronous signal generating section 30 g.

By this step, the piezoelectric element 52 expands and contracts toproduce expanding and contracting force (vibrating force). Thisvibrating force is transmitted to the connection flow path pipe 200 orthe suction pipe 700 via the attachment portion to bend the connectionflow path pipe 200 or the suction pipe 700 in the direction of applyingthe force thereto. The connection flow path pipe 200 or the suction pipe700 vibrates by the bending force and restoring force from the bendedcondition. In this case, larger vibration can be generated from smallerforce by driving the piezoelectric element 52 such that the appliedvibrating force has the natural frequency of the connection flow pathpipe 200 or the suction pipe 700.

After elapse of the given period during which the vibrating force isapplied, the connection of the connection switching section 30 d isswitched to the connection between the supply lines VPZT(−) and VPZT(+)of the piezoelectric element 52 and the vibration detecting section 30 hin response to control signals from the operation control section 30 a.By this step, the given period after switching becomes the detectionperiod by the vibration detecting section 30 h.

By this method, the vibration generating period and the vibrationdetecting period are alternately switched for each given period as shownin FIGS. 17A and 17B.

Then, the level of vibration (electromotive force) during detectionperiod in which the nozzle 211 or the end of the suction pipe 700contacts the affected portion or the like becomes lower than that in theperiod in which the nozzle 211 or the end of the suction pipe 700 doesnot contact the affected portion or the like as can be seen from thevibration waveform in the second half of FIG. 17B.

Thus, the vibration detecting section 30 h detects the electromotiveforce of the piezoelectric element 52 at this time and compares thedetection electromotive force (or average in the correspondingpredetermined period) and the threshold to determine whether thevibration has been decreased. By this step, contact between the nozzle211 or the end of the suction pipe 700 and the affected portion can bedetected.

When detecting the contact between the nozzle 211 or the end of thesuction pipe 700 and the affected portion, the operation control section30 a outputs ejection driving command to the second drive signalsupplying section 30 f.

When non-contact between the nozzle 211 or the end of the suction pipe700 and the affected portion is detected during ejection, the operationcontrol section 30 a outputs ejection stop command to the second drivesignal supplying section 30 f.

When the drive switch is turned off, the operation control section 30 aoutputs ejection stop command to the second drive signal supplyingsection 30 f. After ejection is stopped, the operation control section30 a outputs vibration stop command to the first drive signal supplyingsection 30 b and suspends supply of control signals to the connectionswitching section 30 d.

Other operations are similar to those in the first embodiment, and thusthe same explanation is not repeated.

Accordingly, the fluid ejection device 1 or 3 in this embodiment canperform both application of vibrating force to the connection flow pathpipe 200 or the suction pipe 700 and detection of the level of vibrationgenerated by the applied vibrating force by time division by using thesingle piezoelectric element 52.

Thus, the necessity for providing detection element such as distortiongauge for detecting the level of vibration is eliminated, and thecomponent cost and processing cost associated with the detection elementcan be reduced.

According to the third embodiment, the nozzle 211 and the fluid ejectionopening 212 correspond to a fluid ejection opening as referred to in anyof the first, second, third, fourth and fourteenth aspects. The capacitychanging section 405 and the second drive signal supplying section 30 fcorrespond to a capacity changing unit as referred to in any of thefirst, second, third, thirteenth and fourteenth aspects. The fluidcontainer 10 and the pump 20 correspond to a fluid supplying unit asreferred to in any of the first, second, third, and fourteenth aspects.The suction pipe 700 corresponds to a suction pipe as referred to in anyof the third, sixth and seventh aspects. The suction pump 60 correspondsto a sucking force giving unit as referred to in the third aspect. Thepiezoelectric element 52 and the first drive signal supplying section 30b correspond to a vibrating unit as referred to in the eleventh aspect.The piezoelectric element 52 and the vibration detecting section 30 hcorrespond to a vibration detecting unit as referred to in the eleventhaspect. The operation control section 30 a corresponds to an operationcontrol unit as referred to in any of the first, second, third,thirteenth and fourteenth aspects. The operation control section 30 aand the connection switching section 30 d correspond to a time divisioncontrol unit as referred to in the eleventh aspect. The vibrationdetecting section 30 h corresponds to an electromotive force detectingsection as referred to in the eleventh aspect. The piezoelectric element52 corresponds to a vibrating force generating section as referred to inthe tenth aspect.

Fourth Embodiment

A fourth embodiment according to an aspect of the invention ishereinafter described. FIGS. 18A through 20 show a fluid ejectiondevice, a driving method of a fluid ejection device, and an operatinginstrument according to the fourth embodiment of an aspect of theinvention.

This embodiment is different from the third embodiment in that largervibrating force is applied to the connection flow path pipe 200 or thesuction pipe 700 by using two piezoelectric elements provided on theconnection flow path pipe 200 or the suction pipe 700. Thus, a part ofthe drive unit is different from the drive unit 30′ of the thirdembodiment. Other parts are similar to those of the third embodiment. Inthe following description, only the different parts are discussed indetail. Similar reference numerals are given to similar parts, andexplanation of the similar parts is not repeated.

The attachment structure of the piezoelectric elements 52 and 53 havingfunctions of both application of vibrating force and detection ofvibration in this embodiment is initially described with reference toFIGS. 18A and 18B.

FIG. 18A shows an example of the attachment structure of thepiezoelectric elements 52 and 53 to the connection flow path pipe 200.FIG. 18B shows an example of the attachment structure of thepiezoelectric elements 52 and 53 to the suction pipe 700.

According to this embodiment, application of vibrating force anddetection of the level of vibration are achieved by the twopiezoelectric elements 52 and 53.

In case of the fluid ejection device 1 having no suction pipe, the twopiezoelectric elements 52 and 53 are disposed and fixed to the outercircumferential surface of the connection flow path pipe 200 atpositions shifted toward the nozzle 211 from the outlet flow path pipe510 and opposed to each other with the pipe interposed therebetweensimilarly to the piezoelectric element 50 and the distortion gauge 51 inthe first embodiment as illustrated in FIG. 18A.

The attachment structure of the piezoelectric elements 52 and 53 may beany of the attachment structure of the piezoelectric element 50 and thedistortion gauge 51 shown in FIG. 6 and the structures shown in FIGS. 7Athrough 7D in the first embodiment.

In case of the fluid ejection device 3 having the suction pipe, the twopiezoelectric elements 52 and 53 are disposed and fixed to the outercircumferential surface of the suction pipe 700 at positions closer tothe pulse generating unit 100 and opposed to each other with the pipeinterposed therebetween similarly to the piezoelectric element 50 andthe distortion gauge 51 in the second embodiment as illustrated in FIG.18B.

The attachment structure of the piezoelectric elements 52 and 53 may beany of the attachment structure of the piezoelectric element 50 and thedistortion gauge 51 shown in FIG. 13 and the structures shown in FIGS.14A through 14D in the second embodiment.

The detailed structure of a drive unit 30″ of the fluid ejection device1 or 3 including the piezoelectric elements 52 and 53 for generatingvibrating force and receiving vibration in this embodiment is nowdiscussed with reference to FIG. 19.

FIG. 19 is a block diagram showing the detailed structure of the driveunit 30″ according to this embodiment.

As shown in FIG. 19, the drive unit 30″ includes an operation controlsection 30 a′, a first drive signal supplying section 30 b′, a vibrationdetecting unit 30 h′, a connection switching section 30 d′, the datastoring section 30 e, the second drive signal supplying section 30 f,and the synchronous signal generating section 30 g.

The operation control section 30 a′ has function of issuing operationcommands to the respective components in response to operation inputreceived from the input device of the fluid ejection device 1 or 3. Morespecifically, the operation control section 30 a′ has function ofcontrolling various operation processes such as supplying drive signalsfrom the first drive signal supplying section 30 b′, switching timedivisions associated with the connection switching section 30 d′,determining contact condition of the nozzle 211 or the end of thesuction pipe 700, and supplying drive signals from the second drivesignal supplying section 30 f based on the determination result.

The connection switching section 30 d′ switches between the electricconnection between first supply line VPZT(−) and first supply lineVPZT(+) of the piezoelectric element 52 and second supply line VPZT(−)and second supply line VPZT(+) of the piezoelectric element 53 and thevibration detecting section 30 h, and the electric connection betweenthe first supply line VPZT(−) and the first supply line VPZT(+) of thepiezoelectric element 52 and the second supply line VPZT(−) and thesecond supply line VPZT(+) of the piezoelectric element 53 and the firstdrive signal supplying section 30 b in response to control signals fromthe operation control section 30 a′.

The connection may be switched by using a mechanical switch or switchingelements such as transistors.

The vibration detecting section 30 h′ detects electromotive forcegenerated by piezoelectric effect of the piezoelectric elements 52 and53 having received the vibration of the connection flow path pipe 200 orthe suction pipe 700, and outputs the electromotive force to theoperation control section 30 a′ as detected voltage.

The flow of drive signal supply process to the piezoelectric elements 52and 53 performed by the first drive signal supplying section 30 b′ isnow discussed with reference to FIG. 20.

FIG. 20 is a flowchart showing the drive signal supply process performedby the first drive signal supplying section 30 b′.

When the process for supplying drive signals to the piezoelectricelements 52 and 53 is initiated under the dedicated program executed bythe processor, the flow goes to step S400 as shown in FIG. 20.

In step S400, the first drive signal supplying section 30 b′ determineswhether the vibration generating command is inputted from the operationcontrol section 30 a′. When it is determined that the vibrationgenerating command is inputted (YES), the flow goes to step S402. Whenit is determined that the vibration generating command is not inputted(NO), the determination process is repeated until the command isinputted.

When the flow goes to step S402, the first drive signal supplyingsection 30 b′ reads waveform data for first vibration generation usedfor drive of the piezoelectric element 52 and waveform data for secondvibration generation for drive of the piezoelectric element 53 from thedata storing section 30 e based on the identification information of thespecified waveform contained in the vibration generating command. Then,the flow goes to step S404.

In step S404, the first drive signal supplying section 30 b′ convertsthe digital waveform signals of the first and second waveform data forvibration generation read in step S402 into analog waveform signals.Then, the flow goes to step S406.

In step S406, the first drive signal supplying section 30 b′ outputsdrive signals for first vibration generation having the analog signalwaveform obtained by the D/A conversion in step S404 in synchronizationwith synchronous signals from the synchronous signal generating section30 g to the piezoelectric element 52, and outputs drive signals forsecond vibration generation having the analog signal waveform obtainedby the D/A conversion in step S404 in synchronization with synchronoussignals from the synchronous signal generating section 30 g to thepiezoelectric element 53. Then, the flow goes to step S408.

In step S408, the first drive signal supplying section 30 b′ determineswhether the vibration stop command is inputted from the operationcontrol section 30 a′. When it is determined that the vibration stopcommand is inputted (YES), the flow goes to step S410. When it isdetermined that the vibration stop command is not inputted (NO), thedrive signal output process in step S404 is continued.

When the flow goes to step S410, the first drive signal supplyingsection 30 b′ stops drive signal supply to the piezoelectric elements 52and 53 after output of all signals thereto in one cycle. Then, the flowgoes to step S400.

The operation of the drive unit 30″ according to this embodiment is nowdiscussed.

The drive unit 30″ in this embodiment controls supply contents of thedrive signals to be supplied to the first drive signal supplying section30 b′ in such a manner as to expand and contract the piezoelectricelements 52 and 53 disposed opposed to each other in the directions ofincreasing respective vibrating forces (expanding one of thepiezoelectric elements 52 and 53 and contracting the other) to applylarger vibrating force.

When the drive switch of the WPS is turned on, the drive unit 30″alternately repeats the process for supplying drive signals to thepiezoelectric elements 52 and 53 from the first drive signal supplyingsection 30 b′ for a given period and the process for detecting the levelof vibration by the vibration detecting section 30 h′ for a given periodby time division similarly to the third embodiment so as to perform bothapplication of vibrating force and detection of the level of vibrationgenerated by the applied vibrating force. Thus, the operation controlsection 30 a′ initially controls switching operation of the connectionswitching section 30 d′ by control signals.

More specifically, when the drive switch is turned on, the operationcontrol section 30 a′ alternately switches between the electricconnection between the first supply lines VPZT(−) and VPZT(+) and thesecond supply lines VPZT(−) and VPZT(+) and the first drive signalsupplying section 30 b′ and the electric connection between the firstsupply lines VPZT(−) and VPZT(+) and the second supply lines VPZT(−) andVPZT(+) and the vibration detecting section 30 h′ by time division bycontrolling supply contents of control signals given to the connectionswitching section 30 d′.

Simultaneously, the operation control section 30 a′ outputs vibrationgenerating command to the first drive signal supplying section 30 b′ atthe time of outputting the control signals to the connection switchingsection 30 d′. By this step, the first supply lines VPZT(−) and VPZT(+)of the piezoelectric element 52 and the second supply lines VPZT(−) andVPZT(+) of the piezoelectric element 53 are electrically connected withthe first drive signal supplying section 30 b′, and the vibrationgenerating command is supplied to the first drive signal supplyingsection 30 b′.

When receiving the vibration generating command from the operationcontrol section 30 a′, the first drive signal supplying section 30 b′reads waveform data for the first and second vibration generation fromthe data storing section 30 e and supplies the data to the work memorysuch as RAM. Then, the first drive signal supplying section 30 b′converts the digital waveform data read from the data storing section 30e into analog waveform signals.

Subsequently, the first drive signal supplying section 30 b′ outputs thedrive signals for the first vibration generation thus generated to thepiezoelectric element 52 and outputs the drive signals for the secondvibration generation thus generated to the piezoelectric element 53 insynchronization with synchronous signals from the synchronous signalgenerating section 30 g.

By this step, the piezoelectric elements 52 and 53 expand and contractin the directions of increasing respective forces. For example, thepiezoelectric element 53 contracts when the piezoelectric element 52expands to produce expanding and contracting force (vibrating force).This vibrating force is transmitted to the connection flow path pipe 200or the suction pipe 700 via the attachment portion to bend theconnection flow path pipe 200 or the suction pipe 700 in the directionof applying the force thereto. The connection flow path pipe 200 or thesuction pipe vibrates by the bending force and restoring force from thebended condition. In this case, larger vibration can be generated fromsmaller force by driving the piezoelectric elements 52 and 53 such thatthe applied vibrating force has the natural frequency of the connectionflow path pipe 200 or the suction pipe 700.

After elapse of the given period during which the vibrating force isapplied, the connection of the connection switching section 30 d′ isswitched to the connection between the first supply lines VPZT(−) andVPZT(+) of the piezoelectric element 52 and the second supply linesVPZT(−) and VPZT(+) of the piezoelectric element 53 and the vibrationdetecting section 30 h′ in response to control signals from theoperation control section 30 a′. By this step, the given period afterswitching becomes the detection period by the vibration detectingsection 30 h′.

Thus, the vibration generating period and the vibration detecting periodare alternately switched for each given period. In this case, vibrationwaveform having larger amplitude than that of the amplitude of thevibration waveform shown in FIG. 17A in the third embodiment can begenerated by time division, and the level of vibration can be detectedby time division.

According to this embodiment, both the electromotive forces of thepiezoelectric elements 52 and 53 are detected as detection voltages.However, only one of the electromotive forces may be detected.

Moreover, the vibration detecting section 30 h′ may output therespective electromotive forces of the piezoelectric elements 52 and 53to the operation control section 30 a′ as detected voltages.Alternatively, the vibration detecting section 30 h′ may calculate theaverage of the electromotive forces of the piezoelectric elements 52 and53 and outputs the calculated average to the operation control section30 a′ as the detected voltage.

The determination of the contact or non-contact of the nozzle 211 or theend of the suction pipe 700 by using the detected voltage is similar tothat in the first through third embodiments except that the detectedvoltage is obtained by time division.

Other operations are similar to those performed by the operation controlsection 30 a in the first through third embodiments, and the sameexplanation is not repeated herein.

Accordingly, the fluid ejection device 1 or 3 in this embodiment canexpand and contract the two piezoelectric elements 52 and 53 in thedirections of increasing respective vibrating forces.

By this method, larger vibrating force can be applied to the connectionflow path pipe 200 or the suction pipe 700.

Moreover, application of vibrating force and detection of the level ofthe vibration generated by the vibrating force can be achieved by timedivision by using the piezoelectric elements 52 and 53.

Thus, the necessity for providing detection element such as distortiongauge for detecting the level of vibration is eliminated, and thecomponent cost and processing cost associated with the detection elementcan be reduced.

According to the fourth embodiment, the nozzle 211 and the fluidejection opening 212 correspond to a fluid ejection opening as referredto in any of the first, second, third, fourth and fourteenth aspects.The capacity changing section 405 and the second drive signal supplyingsection 30 f correspond to a capacity changing unit as referred to inany of the first, third, thirteenth and fourteenth aspects. The fluidcontainer 10 and the pump 20 correspond to a fluid supplying unit asreferred to in any of the first and fourteenth aspects. The suction pipe700 corresponds to a suction pipe as referred to in any of the third,sixth and seventh aspects. The suction pump 60 corresponds to a suckingforce giving unit as referred to in the third aspect. The piezoelectricelement 52, the piezoelectric element 53 and the first drive signalsupplying section 30 b′ correspond to a vibrating unit as referred to inthe twelfth aspect. The piezoelectric element 52, the piezoelectricelement 53 and the vibration detecting section 30 h′ correspond to avibration detecting unit as referred to in the eleventh aspect. Theoperation control section 30 a′ corresponds to an operation control unitas referred to in any of the first, thirteenth and fourteenth aspects.The operation control section 30 a′ and the connection switching section30 d′ correspond to a time division control unit as referred to in theeleventh aspect. The vibration detecting section 30 h′ corresponds to anelectromotive force detecting section as referred to in the eleventhaspect. The piezoelectric elements 52 and 53 correspond to a vibratingforce generating section as referred to in the twelfth aspect.

According to the first and second embodiments, the vibration receivingsection is constituted by the metal resistor type distortion gauge 51having resistor formed by resistance line or photo-etched resistancefoil. However, the vibration receiving section may be formed by adistortion gauge of other system such as semiconductor system,piezoelectric element system, surface elastic wave system,magneto-distortion system, and optical fiber system.

According to the first through fourth embodiments, the vibrating forcegenerating unit is constituted by piezoelectric element. However, thevibrating force generating unit may be formed by a component generatingother vibrating force such as solenoid and motor.

According to the first and second embodiments, the piezoelectric element50 and the distortion gauge 51 are fixed to positions opposed to eachother with the pipe interposed therebetween. However, the piezoelectricelement 50 and the distortion gauge 51 may be disposed at otherpositions as long as vibration can be generated and received.

According to the first through fourth embodiments, the piezoelectricelements 50, 52 and 53 and the distortion gauge 51 are disposed on theouter circumferential surface of the connection flow path pipe 200 orthe suction pipe 700 at positions closer to the pulse generating unit100 and opposed to each other with interposed between the piezoelectricelements 50, 52 and 53 and the distortion gauge 51. However, thepiezoelectric elements 50, 52 and 53 and the distortion gauge 51 may belocated at other positions. For example, these components may bedisposed closer to the end of the connection flow path pipe 200 or thesuction pipe 700 or on the inner side of the pipe rather than on theouter circumferential surface of the pipe.

According to the fourth embodiment, larger vibration is generated byusing the two piezoelectric elements 52 and 53. However, vibrating force(generated vibration) may be increased by using three or morepiezoelectric elements.

The first through fourth embodiments and the modified examples describedherein are preferred specific examples of the invention to which variouspreferable limitations in technical view are imposed. However, the scopeof the invention is not limited to these examples as long as anyparticular limitations to the invention are not specified. The figuresused in this specification are only schematic figures having horizontaland vertical reduction scales different from the actual ones for thecomponents and parts to simplify the explanation.

The invention is not limited to the first through fourth embodiments andthe modified examples described herein. It is thus intended thatmodifications, improvements and the like without departing from thescope of the invention are included in the appended claims.

What is claimed is:
 1. A fluid ejection device comprising: a fluidchamber whose capacity is variable; an inlet flow path and an outletflow path communicating with the fluid chamber; a capacity changing unitwhich changes the capacity of the fluid chamber; a fluid supplying unitwhich supplies fluid to the inlet flow path; a fluid ejection openingdisposed at an end of the outlet flow path opposite to an endcommunicating with the fluid chamber; a vibrating unit which vibrates acomponent in the vicinity of the fluid ejection opening; a vibrationdetecting unit which detects the level of vibration of the component inthe vicinity of the fluid ejection opening; and an operation controlunit which controls operation of the capacity changing unit based on thelevel of the vibration detected by the vibration detecting unit.
 2. Thefluid ejection device according to claim 1, wherein the component in thevicinity of the fluid ejection opening forms the fluid ejection opening.3. The fluid ejection device according to claim 1, further comprising: asuction pipe having a suction opening positioned in the vicinity of thefluid ejection opening and a passage through which an object sucked viathe suction opening passes; and a sucking force giving unit which givessucking force for sucking an object in the vicinity of the suctionopening, wherein the component in the vicinity of the fluid ejectionopening forms the suction opening.
 4. The fluid ejection deviceaccording to claim 1, wherein: the vibrating unit has a vibrating forcegenerating section which generates vibrating force for vibrating thefluid ejection opening; the vibration detecting unit has a vibrationreceiving section which receives vibration; and the vibrating forcegenerating section and the vibration receiving section are provided onthe outlet flow path.
 5. The fluid ejection device according to claim 4,wherein: a flat surface is provided at least on a part of the outercircumferential surface of the outlet flow path; and the vibrating forcegenerating section and the vibration receiving section are provided onthe flat surface.
 6. The fluid ejection device according to claim 3,wherein: the vibrating unit has a vibrating force generating sectionwhich generates vibrating force for vibrating the suction opening; thevibration detecting unit has a vibration receiving section whichreceives vibration; and the vibrating force generating section and thevibration receiving section are provided on the suction pipe.
 7. Thefluid ejection device according to claim 6, wherein: a flat surface isprovided at least on a part of the outer circumferential surface of thesuction pipe; and the vibrating force generating section and thevibration receiving section are provided on the flat surface.
 8. Thefluid ejection device according to claim 4, wherein the vibrationreceiving section has a distortion gauge.
 9. The fluid ejection deviceaccording to claim 4, wherein the vibrating force generating section hasa piezoelectric element.
 10. The fluid ejection device according toclaim 9, wherein the vibrating force generating section has function ofgenerating vibrating force and function of receiving vibration as thevibration receiving section by using the piezoelectric element forgenerating vibrating force.
 11. The fluid ejection device according toclaim 10, wherein: the vibrating unit has a drive section which drivesthe piezoelectric element; the vibration detecting unit has anelectromotive force detecting section which detects electromotive forcegenerated on the piezoelectric element; and a time division control unitwhich controls the drive section and the electromotive force detectingsection such that supply of drive signals by the drive section anddetection of electromotive force by the electromotive force detectingsection are performed by time division is provided.
 12. The fluidejection device according to claim 4, wherein: the vibrating unit hasthe plural vibrating force generating sections; and the vibrating unitcontrols operations of the vibrating force generating sections such thatforces generated by the plural vibrating force generating sections canincrease the vibrating force.
 13. The fluid ejection device according toclaim 1, wherein the operation control unit allows operation of thecapacity changing unit when the level of vibration detected by thevibration detecting unit is lower than a predetermined level, andprohibits operation of the capacity changing unit when the level of thevibration is equal to or higher than the predetermined level.
 14. Adriving method of a fluid ejection device comprising: the fluid ejectiondevice including a fluid chamber whose capacity is variable, an inletflow path and an outlet flow path communicating with the fluid chamber,a capacity changing unit which changes the capacity of the fluidchamber, a fluid supplying unit which supplies fluid to the inlet flowpath, a fluid ejection opening disposed at an end of the outlet flowpath opposite to an end communicating with the fluid chamber, avibrating unit, a vibration detecting unit, and an operation controlunit; vibrating a component in the vicinity of the fluid ejectionopening by the vibrating unit; detecting the level of vibration of thecomponent in the vicinity of the fluid ejection opening by the vibrationdetecting unit; and controlling operation of the capacity changing unitbased on the level of the vibration detected in the vibration detectingstep by the operation control unit.
 15. An operating instrument whichsupports medical treatment for an affected portion by using ejection offluid, comprising the fluid ejection device according to claim 1.